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What We Know About COVID-19’s Effects on Child and Maternal Health
Posted on by Dr. Francis Collins
There’s been a lot of focus, and rightly so, on why older adults and adults with chronic disease appear to be at increased risk for coronavirus disease 2019 (COVID-19). Not nearly as much seems to be known about children and COVID-19.
For example, why does SARS-CoV-2, the novel coronavirus that causes COVID-19, seem to affect children differently than adults? What is the psychosocial impact of the pandemic on our youngsters? Are kids as infectious as adults?
A lot of interesting research in this area has been published recently. That includes the results of a large study in South Korea in which researchers traced the person-to-person spread of SARS-CoV-2 in the early days of the pandemic. The researchers found children younger than age 10 spread the virus to others much less often than adults do, though the risk is not zero. But children age 10 to 19 were found to be just as infectious as adults. That obviously has consequences for the current debate about opening the schools.
To get some science-based answers to these and other questions, I recently turned to one of the world’s leading child health researchers: Dr. Diana Bianchi, Director of NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). Dr. Bianchi is a pediatrician with expertise in newborn medicine, neonatology, and reproductive genetics. Here’s a condensed transcript of our chat, which took place via videoconference, with Diana linking in from Boston and me from my home in Chevy Chase, MD:
Collins: What is the overall risk of children getting COVID-19? We initially heard they’re at very low risk. [NOTE: Since the recording of this interview, new data has emerged from state health departments that suggest that as much as 10 percent of new cases of COVID-19 occur in children.]
Bianchi: Biological factors certainly play some role. We know that the virus often enters the body via cells in the nasal passage. A recent study showed that, compared to adults, children’s nasal cells have less of the ACE2 receptor, which the virus attaches to and uses to infect cells. In children, the virus probably has less of an opportunity to grab onto cells and get into the upper respiratory tract.
Importantly, social reasons also play a role in that low percentage. Children have largely been socially isolated since March, when many schools shut down. By and large, young kids have been either home or playing in their backyards.
Collins: If kids do get infected with SARS-CoV-2, the virus that causes COVID-19, what kind of symptoms are displayed?
Bianchi: Children tend to be affected mildly. Relatively few children end up in intensive care units. The most common symptoms are: fever, in about 60 percent of children; cough; and a mild respiratory illness. It’s a different clinical presentation. Children seem to be more prone to vomiting, diarrhea, severe abdominal pain, and other gastrointestinal problems.
Collins: Are children as infectious as adults?
Bianchi: We suspect that older kids probably are. A recently published meta-analysis, or systematic review of the medical literature, also found about 20 percent of infected kids are asymptomatic. There are probably a lot of kids out there who can potentially infect others.
Collins: Do you see a path forward here for schools in the fall?
Bianchi: I think the key word is flexibility. We must remain flexible in the months ahead. Children have struggled from being out of school, and it’s not just the educational loss. It’s the whole support system, which includes the opportunity to exercise. It includes the opportunity to have teachers and school staff looking objectively at the kids to see if they are psychologically well.
The closing of schools has also exacerbated disparities. Schools provide meals for many kids in need, and some have had a lot of food insecurity for the past several months. Not to mention kids in homeless situations often don’t have access to the internet and other learning tools. So, on the whole, being in school is better for children than not being there. That’s how most pediatricians see it. However, we don’t want to put children at risk for getting sick.
Collins: Can you say a little bit more about the consequences, particularly for young children, of being away from their usual areas of social interaction? That’s true this summer as well. Camps that normally would be a place where lots of kids would congregate have either been cancelled or are being conducted in a very different way.
Bianchi: Thus far, most of the published information that we have has really been on the infection and the clinical presentations. Ultimately, I think there will be a lot of information about the behavioral and developmental consequences of not being exposed to other children. I think that older children are also really suffering from not having a daily structure, for example, through sports.
For younger children, they need to learn how to socialize. There are advantages to being with your parents. But there are a lot of social skills that need to be learned without them. People talk about the one-eyed babysitter, YouTube. The American Academy of Pediatrics has issued recommendations for limiting screen time. That’s gone out the window. I’ve talked with a lot of my staff members who are struggling with this balance between educating or entertaining their children and having so-called quality time, and the responsibility to do their jobs.
Collins: What about children with disabilities? Are they in a particularly vulnerable place?
Bianchi: Absolutely. Sadly, we don’t hear a lot about children with disabilities as a vulnerable population. Neither do we hear a lot about the consequences of them not receiving needed services. So many children with disabilities rely on people coming into their homes, whether it’s to help with respiratory care or to provide physical or speech therapy. Many of these home visits are on hold during the pandemic, and that can cause serious problems. For example, you can’t suction a trachea remotely. Of course, you can do speech therapy remotely, but that’s not ideal for two reasons. First, face-to-face interactions are still better, and, secondly, disparities can factor into the equation. Not all kids with disabilities have access to the internet or all the right equipment for online learning.
Collins: Tell me a little bit more about a rare form of consequences from COVID-19, this condition called MIS-C, Multi-System Inflammatory Syndrome of Children. I don’t think anybody knew anything about that until just a couple of months ago.
Bianchi: Even though there were published reports of children infected with SARS-CoV-2 in China in January, we didn’t hear until April about this serious new inflammatory condition. Interestingly, none of the children infected with SARS-CoV-2 in China or Japan are reported to have developed MIS-C. It seemed to be something that was on the European side, predominantly the United Kingdom, Italy, and France. And then, starting in April and May, it was seen in New York and the northeastern United States.
The reason it’s of concern is that many of these children are gravely ill. I mentioned that most children have a mild illness, but the 0.5 percent who get the MIS-C are seriously ill. Almost all require admission to the ICU. The scary thing is they can turn on a dime. They present with more of a prolonged fever. They can have very severe abdominal pain. In some cases, children have been thought to have appendicitis, but they don’t. They have serious cardiac issues and go into shock.
The good news is the majority survive. Many require ventilators and blood-pressure support. But they do respond to treatment. They tend to get out of the hospital in about a week. However, in two studies of MIS-C recently published in New England Journal of Medicine, six children died out of 300 children. So that’s what we want to avoid.
Collins: In terms of the cause, there’s something puzzling about MIS-C. It doesn’t seem to be a direct result of the viral infection. It seems to come on somewhat later, almost like there’s some autoimmune response.
Bianchi: Yes, that’s right. MIS-C does tend to occur, on an average, three to four weeks later. The NIH hosted a conference a couple weeks ago where the top immunologists in the world were talking about MIS-C, and everybody has their piece of the elephant in terms of a hypothesis. We don’t really know right now, but it does seem to be associated with some sort of exuberant, post-infectious inflammatory response.
Is it due to the fact that the virus is still hiding somewhere in the body? Is the body reacting to the virus with excessive production of antibodies? We don’t know. That will be determined, hopefully, within weeks or months.
Collins: And I know that your institute is taking a leading role in studying MIS-C.
Bianchi: Yes. Very shortly after the first cases of MIS-C were being described in the United States, you asked me and Gary Gibbons, director of NIH’s National Heart Lung and Blood Institute, to cochair a taskforce to develop a study designed to address MIS-C. Staff at both institutes have been working, in collaboration with NIH’s National Institute of Allergy and Infectious Diseases, to come up with the best possible way to approach this public health problem.
The study consists of a core group of kids who are in the hospital being treated for MIS-C. We’re obtaining biospecimens and are committed to a central platform and data-sharing. There’s an arm of the study that’s looking at long-term issues. These kids have transient coronary artery dilation. They have a myocarditis. They have markers of heart failure. What does that imply long-term for the function of their hearts?
We will also be working with several existing networks to identify markers suggesting that a certain child is at risk. Is it an underlying immune issue, or is it ethnic background? Is it this a European genomic variant? Exactly what should we be concerned about?
Collins: Let me touch on the genomics part of this for a minute, and that requires a brief description. The SARS-CoV-2 novel coronavirus is crowned in spiky proteins that attach to our cells before infecting them. These spike proteins are made of many amino acids, and their precise sequential order can sometimes shift in subtle ways.
Within that sequential order at amino acid 614, a shift has been discovered. The original Chinese isolate, called the D version, had aspartic acid there. It seems the virus that spread from Asia to the U.S. West Coast also has aspartic acid in that position. But the virus that traveled to Italy and then to the East Coast of the U.S. has a glycine there. It’s called the G version.
There’s been a lot of debate about whether this change really matters. More data are starting to appear suggesting that the G version may be more infectious than the D version, although I’ve seen no real evidence of any difference in severity between the two.
Of course, if the change turned out to be playing a role in MIS-C, you would expect not to have seen so many cases on the West Coast. Has anyone looked to see if kids with the D version of the virus ever get MIS-C?
Bianchi: It hasn’t been reported. You could say that maybe we don’t get all the information from China. But we do get it from Japan. In Japan, they’ve had the D version, and they haven’t had MIS-C.
Collins: Let’s talk about expectant mothers. What is the special impact of COVID-19 on them?
Bianchi: Recently, a lot of information has come out about pregnant women and the developing fetus. A recent report from the Centers for Disease Control and Prevention suggested that pregnant women are at a greatly increased risk of hospitalization. However, the report didn’t divide out hospitalizations that would be expected for delivering a baby from hospitalizations related to illness. But the report did show that pregnant women are at a higher risk of needing respiratory support and having serious illness, particularly if there is an underlying chronic condition, such as chronic lung disease, diabetes or hypertension.
Collins: Do we know the risk of the mother transmitting the coronavirus to the fetus?
Bianchi: What we know so far is the risk of transmission from mother to baby appears to be small. Now, that’s based on the fact that available studies seem to suggest that the ACE2 receptor that the virus uses to bind to our cells, is not expressed in third trimester placental tissue. That doesn’t mean it’s not expressed earlier in gestation. The placenta is so dynamic in terms of gene expression.
What we do know is there’s a lot of ACE2 expression in the blood vessels. An interesting recent study showed in the third trimester placenta, the blood vessels had taken a hit. There was actual blood vessel damage. There was evidence of decreased oxygenation in the placenta. We don’t know the long-term consequences for the baby, but the placentas did not look healthy.
Collins: I have a friend whose daughter recently was ready to deliver her baby. As part of preparing for labor, she had a COVID-19 test. To her surprise and dismay, she was positive, even though she had no symptoms. She went ahead with the delivery, but then the baby was separated from her for a time because of a concern about the mother transmitting the virus to her newborn. Is separation widely recommended?
Bianchi: I think most hospitals are softening on this. [NOTE: The American Academy of Pediatrics recently issued revised recommendations about labor and delivery, as well as about breastfeeding, during COVID-19]
In the beginning, hospitals took a hard line. For example, no support people were allowed into the delivery room. So, women were having more home deliveries, which are far more dangerous, or signing up to give birth at hospitals that allowed support people.
Now more hospitals are allowing a support person in the room during delivery. But, in general, they are recommending that the mother and the support person get tested. If they’re negative, everything’s fine. If the support person is positive, he or she’s not allowed to come in. If the mother is positive, the baby is separated, generally, for testing. In many hospitals, mothers are given the option of reuniting with the baby.
There’s also been a general discussion about mothers who test positive breastfeeding. The more conservative recommendation is to pump the milk and allow somebody else to bottle-feed the baby while the mother recovers from the infection. I should also mention a recent meta-analysis in the United Kingdom. It suggested that a cesarean section delivery is not needed because of SARS-CoV-2 positivity alone. It also found there’s no reason for SARS-CoV-2 positive women not to breast feed.
Collins: Well, Diana, thank you so much for sharing your knowledge. If there’s one thing you wanted parents to take away from this conversation, what would that be?
Bianchi: Well, I think it’s natural to be concerned during a pandemic. But I think parents should be generally reassuring to their children. We’ll get through this. However, I would also say that if a parent notices something unusual going on with a child—skin rashes, the so-called blue COVID toes, or a prolonged fever—don’t mess around. Get your child medical attention as soon as possible. Bad things can happen very quickly to children infected with this virus.
For the expectant parents, hopefully, their obstetricians are counseling them about the fact that they are at high risk. I think that women with chronic conditions really need to be proactive. If they’re not feeling well, they need to go to the emergency room. Again, things can happen quickly with this virus.
But the good news is the babies seem to do very well. There’s no evidence of birth defects so far, and very limited evidence, if at all, of vertical transmission. I think they can feel good about their babies. They need to pay attention to themselves.
Collins: Thank you, Diana, for ending on those wise words.
Bianchi: Thanks, Francis.
Links:
Coronavirus (COVID-19) (NIH)
Diana W. Bianchi, MD, Biosketch of the NICHD Director (Eunice Kennedy Shriver National Institute of Child Health and Human Development/NIH)
Responding to COVID-19, Director’s Corner, NICHD, June 3, 2020
National Child & Maternal Health Education Program (NICHD)
Pregnancy (NICHD)
Meet the Researcher Leading NIH’s COVID-19 Vaccine Development Efforts
Posted on by Dr. Francis Collins
A safe, effective vaccine is the ultimate tool needed to end the coronavirus disease 2019 (COVID-19) pandemic. Biomedical researchers are making progress every day towards such a vaccine, whether it’s devising innovative technologies or figuring out ways to speed human testing. In fact, just this week, NIH’s National Institute of Allergy and Infectious Diseases (NIAID) established a new clinical trials network that will enroll tens of thousands of volunteers in large-scale clinical trials testing a variety of investigational COVID-19 vaccines.
Among the vaccines moving rapidly through the development pipeline is one developed by NIAID’s Dale and Betty Bumpers Vaccine Research Center (VRC), in partnership with Moderna, Inc., Cambridge, MA. So, I couldn’t think of a better person to give us a quick overview of the COVID-19 vaccine research landscape than NIH’s Dr. John Mascola, who is Director of the VRC. Our recent conversation took place via videoconference, with John linking in from his home in Rockville, MD, and me from my place in nearby Chevy Chase. Here’s a condensed transcript of our chat:
Collins: Vaccines have been around since Edward Jenner and smallpox in the late 1700s. But how does a vaccine actually work to protect someone from infection?
Mascola: The immune system works by seeing something that’s foreign and then responding to it. Vaccines depend on the fact that if the immune system has seen a foreign protein or entity once, the second time the immune response will be much brisker. So, with these principles in mind, we vaccinate using part of a viral protein that the immune system will recognize as foreign. The response to this viral protein, or antigen, calls in specialized T and B cells, the so-called memory cells, and they remember the encounter. When you get exposed to the real thing, the immune system is already prepared. Its response is so rapid that you clear the virus before you get sick.
Collins: What are the steps involved in developing a vaccine?
Mascola: One can’t make a vaccine, generally speaking, without knowing something about the virus. We need to understand its surface proteins. We need to understand how the immune system sees the virus. Once that knowledge exists, we can make a candidate vaccine in the laboratory pretty quickly. We then transfer the vaccine to a manufacturing facility, called a pilot plant, that makes clinical grade material for testing. When enough testable material is available, we do a first-in-human study, often at our vaccine clinic at the NIH Clinical Center.
If those tests look promising, the next big step is finding a pharmaceutical partner to make the vaccine at large scale, seek regulatory approval, and distribute it commercially. That usually takes a while. So, from start to finish, the process often takes five or more years.
Collins: With this global crisis, we obviously don’t have five years to wait. Tell us about what the VRC started to do as soon as you learned about the outbreak in Wuhan, China.
Mascola: Sure. It’s a fascinating story. We had been talking with NIAID Director Dr. Anthony Fauci and our colleagues about how to prepare for the next pandemic. Pretty high on our list were coronaviruses, having already worked on past outbreaks of SARS and MERS [other respiratory diseases caused by coronaviruses]. So, we studied coronaviruses and focused on the unique spike protein crowning their surfaces. We designed a vaccine that presented the spike protein to the immune system.
Collins: Knowing that the spike protein was likely your antigen, what was your approach to designing the vaccine?
Mascola: Our approach was a nucleic acid-based vaccine. I’m referring to vaccines that are based on genetic material, either DNA or RNA. It’s this type of vaccine that can be moved most rapidly into the clinic for initial testing.
When we learned of the outbreak in Wuhan, we simply accessed the nucleic acid sequence of SARS-CoV-2, the novel coronavirus that causes COVID-19. Most of the sequence was on a server from Chinese investigators. We looked at the spike sequence and built that into an RNA vaccine. This is called in silico vaccine design. Because of our experience with the original SARS back in the 2000s, we knew its sequence and we knew this approach worked. We simply modified the vaccine design to the sequence of the spike protein of SARS-CoV-2. Literally within days, we started making the vaccine in the lab.
At the same time, we worked with a biotechnology company called Moderna that creates personalized cancer vaccines. From the time the sequence was made available in early January to the start of the first in-human study, it was about 65 days.
Collins: Wow! Has there ever been a vaccine developed in 65 days?
Mascola: I don’t think so. There are a lot of firsts with COVID, and vaccine development is one of them.
Collins: For the volunteers who enrolled in the phase 1 study, what was actually in the syringe?
Mascola: The syringe included messenger RNA (mRNA), the encoded instructions for making a specific protein, in this case the spike protein. The mRNA is formulated in a lipid nanoparticle shell. The reason is mRNA is less stable than DNA, and it doesn’t like to hang around in a test tube where enzymes can break it down. But if one formulates it just right into a nanoparticle, the mRNA is protected. Furthermore, that protective particle allows one to inject it into muscle and facilitates the uptake of the mRNA into the muscle cells. The cells translate the mRNA into spike proteins, and the immune system sees them and mounts a response.
Collins: Do muscle cells know how to take that protein and put it on their cell surfaces, where the immune system can see it?
Mascola: They do if the mRNA is engineered just the right way. We’ve been doing this with DNA for a long time. With mRNA, the advantage is that it just has to get into the cell [not into the nucleus of the cell as it does for DNA]. But it took about a decade of work to figure out how to do nucleotide silencing, which allows the cell to see the mRNA, not destroy it, and actually treat it as a normal piece of mRNA to translate into protein. Once that was figured out, it becomes pretty easy to make any specific vaccine.
Collins: That’s really an amazing part of the science. While it seems like this all happened in a blink of an eye, 65 days, it was built on years of basic science work to understand how cells treat mRNA. What’s the status of the vaccine right now?
Mascola: Early data from the phase 1 study are very encouraging. There’s a manuscript in preparation that should be out shortly showing that the vaccine was safe. It induced a very robust immune response to that spike protein. In particular, we looked for neutralizing antibodies, which are the ones that attach to the spike, blocking the virus from binding to a cell. There’s a general principle in vaccine development: if the immune system generates neutralizing antibodies, that’s a very good sign.
Collins: You’d be the first to say that you’re not done yet. Even though those are good signs, that doesn’t prove that this vaccine will work. What else do you need to know?
Mascola: The only real way to learn if a vaccine works is to test it in people. We break clinical studies into phases 1, 2, and 3. Phase 1 has already been done to evaluate safety. Phase 2 is a larger evaluation of safety and immune response. That’s ongoing and has enrolled 500 or 600 people, which is good. The plan for the phase 3 study will be to start in July. Again, that’s incredibly fast, considering that we didn’t even know this virus existed until January.
Collins: How many people do you need to study in a phase 3 trial?
Mascola: We’re thinking 20,000 or 30,000.
Collins: And half get the vaccine and half get a placebo?
Mascola: Sometimes it can be done differently, but the classic approach is half placebo, half vaccine.
Collins: We’ve been talking about the VRC-Moderna nucleic acid vaccine. But there are others that are coming along pretty quickly. What other strategies are being employed, and what are their timetables?
Mascola: There are many dozens of vaccines under development. The response has been extraordinary by academic groups, biotech companies, pharmaceutical companies, and NIH’s Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) partnership. I don’t think I’ve ever seen so much activity in a vaccine space moving ahead at such a rapid clip.
As far as being ready for advanced clinical trials, there are a just handful and they involve different types of vaccines. At least three nucleic acid vaccines are in clinical trials. There are also two vaccines that use proteins, which is a more classic approach.
In addition, there are several vaccines based on a viral vector. To make these, one puts the genes for the spike protein inside an adenovirus, which is an innocuous cold virus, and injects it into muscle. In regard to phase 3 trials, there are maybe three or four vaccines that could be formally in such tests by the fall.
Collins: How is it possible to do this so much more rapidly than in the past, without imposing risks?
Mascola: It’s a really important question, Francis. A number of things are being done in parallel, and that wouldn’t usually be the case. We can get a vaccine into a first-in-human study much more quickly because of time-saving technologies.
But the real important point is that for the phase 3 trial, there are no timesavers. One must enroll 30,000 people and watch them over months in a very rigorous, placebo-controlled environment. The NIH has stood up what’s called a Data Safety Monitoring Board for all the trials. That’s an independent group of investigators that will review all vaccine trial data periodically. They can see what the data are showing: Should the trial be stopped early because the vaccine is working? Is there a safety signal that raises concern?
While the phase 3 trial is going on, the U.S. government also will be funding large-scale manufacture of the vaccine. Traditionally, you would do the vaccine trial, wait until it’s all done, and analyze the data. If it worked, you’d build a vaccine plant to make enough material, which takes two or three years, and then go to the Food and Drug Administration (FDA) for regulatory approval.
Everything here is being done in parallel. So, if the vaccine works, it’s already in supply. And we have been engaging the FDA to get real-time feedback. That does save a lot of time.
Collins: Is it possible that we’ll manufacture a whole lot of doses that may have to be thrown out if the vaccine doesn’t work?
Mascola: It certainly is possible. One would like to think that for coronaviruses, vaccines are likely to work, in part because the natural immune response clears them. People get quite sick, but eventually the immune system clears the virus. So, if we can prime it with a vaccine, there is reason to believe vaccines should work.
Collins: If the vaccine does work, will this be for lifelong prevention of COVID-19? Or will this be like the flu, where the virus keeps changing and new versions of the vaccine are needed every year?
Mascola: From what we know about coronaviruses, we think it’s likely COVID-19 is not like the flu. Coronaviruses do have some mutation rate, but the data suggest it’s not as rapid as influenza. If we’re fortunate, the vaccine won’t need to be changed. Still, there’s the matter of whether the immunity lasts for a year, five years, or 10 years. That we don’t know without more data.
Collins: Do we know for sure that somebody who has had COVID-19 can’t get it again a few months later?
Mascola: We don’t know yet. To get the answer, we must do natural history studies, where we follow people who’ve been infected and see if their risk of getting the infection is much lower. Although classically in virology, if your immune system shows neutralizing antibodies to a virus, it’s very likely you have some level of immunity.
What’s a bit tricky is there are people who get very mild symptoms of COVID-19. Does that mean their immune system only saw a little bit of the viral antigen and didn’t respond very robustly? We’re not sure that everyone who gets an infection is equally protected. That’s going to require a natural history study, which will take about a year of follow-up to get the answers.
Collins: Let’s go back to trials that need to happen this summer. You talked about 20,000 to 30,000 people needing to volunteer just for one vaccine. Whom do you want to volunteer?
Mascola: The idea with a phase 3 trial is to have a broad spectrum of participation. To conduct a trial of 30,000 people is an enormous logistical operation, but it has been done for the rotavirus and HPV vaccines. When you get to phase 3, you don’t want to enroll just healthy adults. You want to enroll people who are representative of the diverse population that you want to protect.
Collins: Do you want to enrich for high-risk populations? They’re the ones for whom we hope the vaccine will provide greatest benefit: for example, older people with chronic illnesses, African Americans, and Hispanics.
Mascola: Absolutely. We want to make sure that we can feel comfortable to recommend the vaccine to at-risk populations.
Collins: Some people have floated another possibility. They ask why do we need expensive, long-term clinical trials with tens of thousands of people? Couldn’t we do a human challenge trial in which we give the vaccine to some healthy, young volunteers, wait a couple of weeks, and then intentionally expose them to SARS-CoV-2. If they don’t get sick, we’re done. Are challenge studies a good idea for COVID-19?
Mascola: Not right now. First, one has to make a challenge stock of the SARS-CoV-2 that’s not too pathogenic. We don’t want to make something in the lab that causes people to get severe pneumonia. Also, for challenge studies, it would be preferable to have a very effective small drug or antibody treatment on hand. If someone were to get sick, you could take care of the infection pretty readily with the treatments. We don’t have curative treatments, so the current thinking is we’re not there yet for COVID-19 challenge studies [1]. If you look at our accelerated timeline, formal vaccine trials still may be the fastest and safest way to get the answers.
Collins: I’m glad you’re doing it the other way, John. It’s going to take a lot of effort. You’re going to have to go somewhere where there is still ongoing spread, otherwise you won’t know if the vaccine works or not. That’s going to be tricky.
Mascola: Yes. How do we know where to test the vaccine? We are using predictive analytics, which is just a fancy way of saying that we are trying to predict where in the country there will be ongoing transmission. If we can get really good at it, we’ll have real-time data to say transmission is ongoing in a certain area. We can vaccinate in that community, while also possibly protecting people most at risk.
Collins: John, this conversation has been really informative. What’s your most optimistic view about when we might have a COVID-19 vaccine that’s safe and effective enough to distribute to the public?
Mascola: An optimistic scenario would be that we get an answer in the phase 3 trial towards the end of this year. We have scaled up the production in parallel, so the vaccine should be available in great supply. We still must allow for the FDA to review the data and be comfortable with licensing the vaccine. Then we must factor in a little time for distributing and recommending that people get the vaccine.
Collins: Well, it’s wonderful to have someone with your skills, experience, and vision taking such a leading role, along with your many colleagues at the Vaccine Research Center. People like Kizzmekia Corbett, Barney Graham, and all the others who are a part of this amazing team that you’ve put together, overseen by Dr. Fauci.
While there is still a ways to go, we can take pride in how far we have come since this virus emerged just about six months ago. In my 27 years at NIH, I’ve never seen anything quite like this. There’s been a willingness among people to set aside all kinds of other concerns. They’ve gathered around the same table, worked on vaccine design and implementation, and gotten out there in the real world to launch clinical trials.
John, thank you for what you are doing 24/7 to make this kind of progress possible. We’re all watching, hoping, and praying that this will turn out to be the answer that people desperately need after such a terribly difficult time so far in 2020. I believe 2021 will be a very different kind of experience, largely because of the vaccine science that we’ve been talking about today.
Mascola: Thank you so much, Francis. And thanks for recognizing all the people behind the scenes who are making this happen. They’re working really hard!
Reference:
[1] Accelerating Development of SARS-CoV-2 Vaccines—The Role for Controlled Human Infection Models. Deming ME, Michael, NL, Robb M, Cohen MS, Neuzil KM. N Engl J Med. 2020 July 1. [Epub ahead of print].
Links:
Coronavirus (COVID-19) (NIH)
John R. Mascola (National Institute of Allergy and Infectious Diseases/NIH)
Novel Vaccine Technologies for the 21st Century. Mascola JR, Fauci AS. Nat Rev Immunol. 2020 Feb;20(2):87-88.
Vaccine Research Center (NIAID/NIH)
Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV)
Swimming with the High-Tech Sharks to Improve COVID-19 Testing
Posted on by Dr. Francis Collins
So much has been reported over the past six months about testing for coronavirus disease 2019 (COVID-19) that keeping up with the issue can be a real challenge. To discuss the latest progress on new technologies for SARS-CoV-2 diagnostic testing in the United States, I spoke recently with NIH’s Dr. Bruce Tromberg, director of the National Institute of Biomedical Imaging and Bioengineering (NIBIB). Not only does Bruce run a busy NIH institute, he is helping to coordinate the national response for expanded testing during the COVID-19 pandemic.
Bruce also has a leading role in one of NIH’s most-exciting new initiatives. It’s called the Rapid Acceleration of Diagnostics (RADx) initiative, and it is on the fast track to bolster the country’s diagnostic testing capacity within months. Here’s a condensed transcript of our chat, which took place via videoconference, with Bruce linking in from Bethesda, MD and me from my home in Chevy Chase, MD:
Collins: Let’s start with how many COVID-19 tests are being done right now per day in the United States. By that, I’m referring to testing for the presence of the novel coronavirus, not antibodies as a sign of a previous infection.
Tromberg: The numbers fluctuate—anywhere from around 400,000 to 900,000 tests per day. So, the national capacity, with all these complex laboratory tests and emerging point-of-care assays, is getting close to 1 million a day. That’s substantially higher than in mid-April, when the nation was doing about 150,000 tests per day. But most testing is still being done in laboratories or complex facilities, and it can take a while for those tests to be run and for people to get answers. What we’d like to have are more convenient tests. We’d like to have tests that people can have at the point of care, where you get an answer on the spot and very quickly, or tests that can be performed easily in their homes.
Collins: Yes, we’d all love to have point-of-care tests for COVID-19. And there are some out there already. Every time I go to the White House, they have this gadget, called Abbott ID Now, that gives a result in about 15 minutes. That sounds pretty good. Do we just need to make more of those machines to solve the problem?
Tromberg: Abbott ID Now is one of the first point-of-care technologies. It’s not complicated, so a specialized laboratory isn’t required to run them. That’s what makes Abbott ID Now very appealing, but its performance could be better. There’s a bit of a risk when it’s used in individuals for which you really need to know, with absolute certainty, if they have the virus or not. Those performance issues have created opportunities to build platforms that are better, faster, and possible for people to do on their own.
Collins: Congress provided a big infusion of resources last April to assist in the development of new diagnostic technologies for COVID-19. A lot of that infusion came to NIH, and, Bruce, you were asked to step in and make something amazing happen on a timetable that’s pretty breathtaking. It’s called the RADx Initiative. Tell us a little about that.
Tromberg: RADx is short for Rapid Acceleration of Diagnostics. The goal of the initiative is to make it possible for everyone to have access to diagnostic testing for COVID-19 as easily and quickly as possible. As we pivot to doing surveillance in large populations, we will need greater testing capacity to help optimize the management of each individual. So, that’s really the aim of RADx, or RADx-tech, which is a special flavor of RADx.
Collins: Right, the goal of RADx-tech, which you are overseeing, is to identify some of these exciting new technologies and help scale them up quickly to the point where they can help people across the nation. Could you give us some examples?
Tromberg: Sure. One general class of technologies is called a lateral flow assay. These tests are small enough to fit in your hand and come in a convenient container. Basically, you can use a swab from your oral cavity and place it on one of the pads, and then you add a little bit of solution. The actual assay itself has a membrane inside of a little plastic container. The fluid flows across the membrane, and there’s chemistry that goes on inside the container to detect, for example, genetic material from the coronavirus. So, it can tell you if there is a presence of virus inside the swab. It’s very quick and straightforward. A line will “light up” if virus is present.
Another type of lateral flow assay, also small enough to hold in your hand, looks for proteins on the surface of the virus. You don’t have to break up the virus particle itself, but in this specific example, what captures the virus in this membrane is what’s called an aptamer. An aptamer is similar to an antibody, except it’s made from nucleic acid. It’s designed to bind very tightly with any molecule of interest. If you put a saliva sample into this assay, it moves up the membrane and some chemistry takes place. And then, you’ll see a line appear if there’s presence of a virus.
Collins: You just said saliva. I think a lot of people would much prefer, if they had to provide a sample, to use saliva instead of having a swab stuck in their nose, especially if it has to go all the way to the back of the nose. Does saliva work?
Tromberg: We hope so. Right now, RADx-tech has at least nine companies that are in what we call phase one, which is a significant step towards commercialization. Of those companies, more than half are looking at saliva or other kinds of sampling that’s not sticking swabs way up into the nasal cavity.
Another type of test is a lateral flow assay that fits directly into a mobile device like a tablet. It has a separate lateral flow apparatus, which looks like an elongated zip drive, and it slides right into the tablet itself. It’s something that’s not complicated. It would be easy to do at home. But rather than watching for the presence of a reaction, you look for a light inside the tablet to say the result is ready. And then, there is another color of light that comes directly from the lateral flow strip, that’s an indicator that the virus is present.
One last example is a nucleic acid test. This rectangular, hand-held device (see photo), reminiscent of a computer disc, looks inside the virus to amplify small traces of its nucleic acid to detectable levels. It is completely self-contained. To find that technology today, you generally must go to complex laboratories where the test is done on big machines, operated in multiple steps. Efforts are being made to reduce the size and the complexity of these devices so they can move out to point of care, without sacrificing the performance that we expect from a laboratory-based device.
Collins: That’s totally cool. Is the nucleic-acid test device that you just mentioned made for one-time use, and then you throw it away?
Tromberg: That’s their business model right now. I should probably mention something about cost. For example, you can imagine scaling up lateral flow assays very quickly to make tens of millions of tests. The components are inexpensive, and the tests may cost just a few dollars to make.
If you’re throwing away a nucleic acid test with its more-expensive components, obviously, the cost will be higher. Right now, if you go to a laboratory for a nucleic acid test, the cost may be on the order of $40 or so. With these one-time-use nucleic acid tests, the aim is to scale up the manufacturing to produce larger volumes that will bring the cost down. The estimates are maybe $60 per test.
Collins: That needs to come down more, obviously. In the months ahead, we’re talking about testing millions of people, maybe even fairly often to make sure that they haven’t been infected by SARS-CoV-2, the novel coronavirus that causes COVID-19. Is frequent testing the kind of thing that you’d like to be able to do by next fall?
Tromberg: Yes, and I think that that really speaks to the diversity of the types of tests that we need. I think there is a market, or the capacity, for some of the more expensive tests, if they’re extremely accurate and convenient. So, the nucleic acid test may cost more, but it will give you an answer very quickly and with very high sensitivity. It’s also very convenient. But the performance of that test may be very different from a standard lateral flow assay. Those tests will be far more accessible and very, very inexpensive, but they may have a higher false negative rate. We envision that every test that comes out of our innovation funnel will have documentation about its best-use case.
Collins: You mentioned your innovation funnel, sometimes called a “shark tank.” Say a little more about the RADx-tech shark tank. Who gets into it, and what happens when they get there?
Tromberg: At NIH, we’re into processes, and NIBIB created a very effective one 13 years ago with the Point of Care Technology Research Network (POCTRN). We’ve now leveraged this network to focus almost exclusively on COVID testing. POCTRN has five sites in the US. All have core resources, personnel, and expertise that are contributing to RADx-tech. Those include the ability to validate tests independently, the ability to do clinical studies in real-world samples and patients, and the ability to analyze manufacturing and scale-up needs while creating a roadmap for every project team to follow.
We have more than 200 people around the country working day and night on this process. If anyone has an idea about a COVID-19 test, you can and apply for funding on the POCTRN website. Your application will be reviewed by a panel of 30 experts within a day and, if approved, will move to the next stage, which is the shark tank.
In the shark tank [also called phase zero], a team of experts will spend about 150 to 200 person-hours with you evaluating the strengths and weaknesses of your test technically, clinically, and commercially. From this careful analysis, a detailed proposal will be presented to a steering committee, then sent to NIH. If we think it’s a great idea, the project will enter what we call phase one, with considerable financial support and the expectation that the company will hit its validation milestones within a month.
Collins: How far have things progressed, given that you just started RADx on April 29?
Tromberg: We have almost 60 projects that have entered or emerged from this shark-tank stage. I’m expecting that we’ll have around 15 projects in the phase one stage this month, and it’s very exciting to see them move there. If they can reach their validation milestones in that first month, they will be eligible to move to phase two. It involves a much larger chunk of money, so companies can move into manufacturing and scale up for distribution. We’re hoping to have between five and 10 companies emerge over time from this innovation funnel. But, by the end of the summer, we’d like to see at least two come out with products that will make a difference.
Collins: Wow, that’s just a few months away. How will you can get there so fast?
Tromberg: Sure. Some companies are further along than others. I can think of one that is quite far along with an established platform concept. This company has lots of expertise and has raised lots of money. We may be able to give them the surge that they need, plus the additional support with regulatory issues, commercialization, and manufacturing, in that short period of time to go to market.
Complementing that work is another of our initiatives called Advanced Technology Platforms (RADx-ATP). It’s designed to scale up existing technologies. For example, I mentioned a one-time-use nucleic acid test. It still needs validation, emergency use authorization, a little bit of manufacturing optimization. But we have other platforms out there that are much closer to commercialization, and RADx-ATP could be very impactful in getting some of those technologies out earlier.
Collins: You mentioned RADx-ATP, and we’ve been talking about RADx-tech, which is your shark tank approach. But there are a couple of other RADx components. Say something about those, please.
Tromberg: Our centerpiece component for doing demonstration projects is called RADx-UP. This is an effort across NIH to provide cutting-edge testing technologies in underserved populations. If I’m allowed to be the interviewer and turn the tables, I might bounce the question back to you. This is where your thinking directly influenced the whole RADx portfolio. So, maybe you can tell us more.
Collins: I can try. It’s very clear that COVID-19 has hit certain populations particularly hard, especially African American and Hispanic communities. And yet, those communities often have the least access to testing, which is sort of upside-down. We want to help identify people who are infected quickly, do the quarantining, and prevent the infection from spreading. That has simply not worked very well in a lot of underserved communities.
With resources from Congress, we made it a very high priority to set up demonstration projects of these advanced technologies in communities that would benefit significantly from them. We’re trying to bring together two really important NIH priorities: technology development and addressing health disparities. I’ve got to say, at this particular moment, when we’re all really focused on the fact that our nation is still riddled with health disparities, health inequities, and even racism, this is a moment where we should be doing everything we can to try to take our scientific capabilities and apply them to finding solutions.
So, we’re all pretty excited about RADx-UP. But there’s one other RADx, and I’ll throw this one back to you. It’s called RADx-rad. What the heck is that, Bruce?
Tromberg: Well, RADx-rad is the home for the technologies that are really far forward and futuristic. These are the technologies that won’t quite be ready for the time pressure of the innovation funnel. But they’re fantastic ideas. They’re projects that may be non-traditional in terms of the application of technology. They have been generated largely by other NIH institutes and centers. They’re important ideas and projects that just need to be supported with a longer time-window of return. We don’t want to lose out on the energy and the ideas and the creativity of those concepts.
Collins: Right now, the focus is on COVID-19 and the need for testing, especially within this calendar year. We hope, by the end of 2020 or the early part of 2021, to have vaccines for COVID-19 ready to go. But, moving forward, there will be other events that will probably make us wish that we had point-of-care diagnostics. So, in the process of doing what you’re doing with all of these components, hopefully we’re also preparing for future challenges.
Bruce, you’re an optimistic guy. At the same time, we’ve got to be realistic. Around September, when schools and colleges are contemplating whether it’s safe to open up, what would we hope that RADx could contribute to make that a better outcome?
Tromberg: That’s a tough question to answer, but I have a lot of confidence in our process. I’m confident that we’re engaging the innovation and entrepreneurial community in such a way that a lot of these ideas will move out and give us better performing tests and more of them. A rough number that I like to think about is the capacity to test roughly 2 percent of the population, around 6 million people per day. I think we’ll hit that target by the end of the year.
I’d like to see testing technologies move away from being based predominantly in laboratories. I’d like to see them more accessible to people as technologies that they can use in their homes. We’re now doing so many things from home. We’re working from home, we’re talking from home, we get our entertainment from home. Home-based testing is really the direction a lot of healthcare is going. We need to have these technologies. I think the level of sophistication and performance that we’re hoping for is possible, and the innovation and entrepreneurial community is working extremely hard to make it happen. No one has really asked us to do anything of this scale before, and I like to compare it to our Super Bowl.
Collins: Well, this is one exciting Super Bowl, that’s for sure! You’ve applied the venture capitalist strategy to RADx of trying to discover what’s out there, while not being afraid to invest in risky endeavors. You’re figuring out how to help promising technologies take their best shot and fail early, if they’re going to fail. And for technologies that are further along, you give them the needed resources to advance to commercialization.
We have great hopes and expectations that RADx will make a real difference. What we’re doing here is not just about cool science, it’s also about saving lives. I want to thank you for your incredible dedication, and your intellectual and engineering contributions to this initiative, which make it one of the most exciting things that NIH is doing right now.
Tromberg: Thank you, Francis.
Links:
Coronavirus (COVID-19) (NIH)
Rapid Acceleration of Diagnostics (RADx)
“Social engineering and bioengineering together can thwart the COVID-19 pandemic,” Director’s Corner, National Institute of Biomedical Imaging and Bioengineering/NIH)
Video: RADx Tech and POCTRN: Diagnosing Disease-Delivering Health (NIBIB/NIH)
Searching for Ways to Prevent Life-Threatening Blood Clots in COVID-19
Posted on by Dr. Francis Collins
Six months into the coronavirus disease 2019 (COVID-19) pandemic, researchers still have much to learn about the many ways in which COVID-19 can wreak devastation on the human body. Among the many mysteries is exactly how SARS-CoV-2, which is the novel coronavirus that causes COVID-19, triggers the formation of blood clots that can lead to strokes and other life-threatening complications, even in younger people.
Recently, I had a chance to talk with Dr. Gary Gibbons, Director of NIH’s Heart, Lung, and Blood Institute (NHLBI) about what research is being done to tackle this baffling complication of COVID-19. Our conversation took place via videoconference, with him connecting from his home in Washington, D.C., and me linking in from my home just up the road in Maryland. Here’s a condensed transcript of our chat:
Collins: I’m going to start by asking about the SARS-CoV-2-induced blood clotting not only in the lungs, but in other parts of the body. What do we know about the virus that would explain this?
Gibbons: It seems like every few weeks another page gets turned on COVID-19, and we learn even more about how this virus affects the body. Blood clots are one of the startling and, unfortunately, devastating complications that emerged as patients were cared for, particularly in New York City. It became apparent that certain individuals had difficulty getting enough oxygen into their system. The difficulty couldn’t be explained entirely by the extent of the pneumonia affecting the lungs’ ability to exchange oxygen.
It turned out that, in addition to the pneumonia, blood clots in the lungs were compromising oxygenation. But some patients also had clotting, or thrombotic, complications in their veins and arteries in other parts of the body. Quite puzzling. There were episodes of relatively young individuals in their 30s and 40s presenting with strokes related to blood clots affecting the arterial circulation to the brain.
We’re still trying to understand what promotes the clotting. One clue involves the endothelial cells that form the inner lining of our blood vessels. These cells have on their surface a protein called the angiotensin-converting enzyme 2 (ACE2) receptor, and this clue is important for two reasons. One, the virus attaches to the ACE2 receptor, using it as an entry point to infect cells. Two, endothelial-lined blood vessels extend to every organ in the body. Taken together, it seems that some COVID-19 complications relate to the virus attaching to endothelial cells, not only in the lungs, but in the heart and multiple organs.
Collins: So, starting in the respiratory tree, the virus somehow breaks through into a blood vessel and then gets spread around the body. There have been strange reports of people with COVID-19 who may not get really sick, but their toes look frostbitten. Is “COVID toes,” as some people call it, also part of this same syndrome?
Gibbons: We’re still in the early days of learning about this virus. But I think this offers a further clue that the virus not only affects large vessels but small vessels. In fact, clots have been reported at the capillary level, and that’s fairly unusual. It’s suggestive that an interaction is taking place between the platelets and the endothelial surface.
Normally, there’s a tightly regulated balance in the bloodstream between pro-coagulant and anticoagulant proteins to prevent clotting and keep the blood flowing. But when you cut your finger, for example, you get activation for blood clots in the form of a protein mesh. It looks like a fishing net that can help seal the injury. In addition, platelets in the blood stream help to plug the holes in that fishing net and create a real seal of a blood vessel.
Well, imagine it happening in those small vessels, which usually have a non-stick endothelial surface, almost like Teflon, that prevents clotting. Then the virus comes along and tips the balance toward promoting clot formation. This disturbs the Teflon-like property of the endothelial lining and makes it sticky. It’s incredible the tricks this virus has learned by binding onto one of these molecules in the endothelial lining.
Collins: Who are the COVID-19 patients most at risk for this clotting problem?
Gibbons: Unfortunately, it appears right now that older adults are among the most vulnerable. They have a lot of the risks for the formation of these blood clots. What’s notable is these thrombotic complications are also happening to relatively young adults or middle-aged individuals who don’t have a lot of other chronic conditions, or comorbidities, to put them at higher risk for severe disease. Again, it’s suggestive that this virus is doing something that is particular to the coagulation system.
Collins: We’d love to have a way of identifying in advance the people who are most likely to get into trouble with blood clotting. They might be the ones you’d want to start on an intervention, even before you have evidence that things are getting out of control. Do you have any kind of biomarker to tell you which patients might benefit from early intervention?
Gibbons: Biomarkers are being actively studied. What we do know from some earlier observations is that you can assess the balance of clotting and anticlotting factors in the blood by measuring a biomarker called D-dimer. It’s basically a protein fragment, a degradation product, from a prior clot. It tells you a bit about the system’s activity in forming and dissolving clots.
If there’s a lot of D-dimer activity, it suggests a coagulation cascade is jazzed up. In those patients, it’s probably a clue that this is a big trigger in terms of coagulation and thrombosis. So, D-dimer levels could maybe tell us which patients need really aggressive full anticoagulation.
Collins: Have people tried empirically using blood thinners for people who seem to be getting into trouble with this clotting problem?
Gibbons: There’s a paper out of the Mount Sinai in New York City that looked at thousands of patients being treated for COVID-19 [1]. Based on clinical practice and judgments, one of the striking findings is that those who were fully anticoagulated had better survival than those who were not. Now, this was not a randomized, controlled clinical trial, where some were given full anticoagulation and others were not. It was just an observational study that showed an association. But this study indicated indirectly that by giving the blood thinners, changing that thrombotic risk, maybe it’s possible to reduce morbidity and mortality. That’s why we need to do a randomized, controlled clinical trial to see if it can be used to reduce these case fatality rates.
Collins: You and your colleagues got together and came up with a design for such a clinical trial. Tell us about that.
Gibbons: My institute studies the heart, lung, and blood. The virus attacks all three. So, our community has a compelling need to lean in and study COVID-19. Recently, NIH helped to launch a public-private partnership called Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV). As the name spells out, this initiative provides is a clinical platform to generate life-saving treatments as we wait for the development of a vaccine.
Through ACTIV, a protocol is now in the final stages of review for a clinical trial that will involve a network of hospitals and explore the question: is it sufficient to try a low-dose thrombo-prophylactic, or clot preventative, approach versus full anticoagulation? Some think patients ought to have full anticoagulation, but that’s not without risk. So, we want to put that question to the test. As part of that, we’ll also learn more about biomarkers and what could be predictive of individuals getting the greatest benefit.
If we find that fully anticoagulating patients prevents clots, then that’s great. But it begs the question: what happens when patients go home? Is it sufficient to just turn off the drip and let them go their merry way? Should they have a low dose thrombo-prophylactic regimen for a period of time? If so, how long? Or should they be fully anticoagulated with oral anticoagulation for a certain period of time? All these and other questions still remain.
Collins: This can make a huge difference. If you’re admitted to the hospital with COVID-19, that means you’re pretty sick and, based on the numbers that I’ve seen, your chance of dying is about 12 percent if nothing else happens. If we can find something like an anticoagulant that would reduce that risk substantially, we can have a huge impact on reducing deaths from COVID-19. How soon can we get this trial going, Gary?
Gibbons: We have a sense of urgency that clearly this pandemic is taking too many lives and time is of the essence. So, we’ve indeed had a very streamlined process. We’re leveraging the fact that we have clinical trial networks, where regardless of what they were planning to do, it’s all hands on deck. As a result, we’re able to move faster to align with that sense of urgency. We hope that we can be off to a quick launch within the next two to three weeks with the anticoagulation trials.
Collins: This is good because people are waiting on the vaccines, but realistically we won’t know whether the vaccines are working for several more months, and having them available for lots of people will be at the very end of this year or early 2021 at best. Meanwhile, people still are going to be getting sick with COVID-19. We want to be able to have as many therapeutic options as possible to offer to them. And this seems like a pretty exciting one to try and move forward as quickly as possible. You and your colleagues deserve a lot of credit for bringing this to everybody’s attention.
But before we sign off, I have to raise another issue of deep significance. Gary, I think both of us are struggling not only with the impact of COVID-19 on the world, but the profound sorrow, grief, frustration, and anger that surrounds the death of George Floyd. This brings into acute focus the far too numerous other circumstances where African Americans have been mistreated and subjected to tragic outcomes.
This troubling time also shines a light on the health disparities that affect our nation in so many ways. We can see what COVID-19 has done to certain underrepresented groups who have borne an undue share of the burden, and have suffered injustices at the hands of society. It’s been tough for many of us to admit that our country is far from treating everyone equally, but it’s a learning opportunity and a call to redouble our efforts to find solutions.
Gary, you’ve been a wonderful leader in that conversation for a long time. I want to thank you both for what you’re doing scientifically and for your willingness to speak the truth and stand up for what’s right and fair. It’s been great talking to you about all these issues.
Gibbons: Thank you. We appreciate this opportunity to fulfill NIH’s mission of turning scientific discovery into better health for all. If there’s any moment that our nation needs us, this is it.
Reference:
[1] Association of Treatment Dose Anticoagulation With In-Hospital Survival Among Hospitalized Patients With COVID-19. Paranjpe I, Fuster V, Lala A, Russak A, Glicksberg BS, Levin MA, Charney AW, Narula J, Fayad ZA, Bagiella E, Zhao S, Nadkarni GN. J Am Coll Cardiol. 2020 May 5;S0735-1097(20)35218-9.
Links:
Coronavirus (COVID-19) (NIH)
“Rising to the Challenge of COVID-19: The NHLBI Community Response,” Director’s Messages, National Heart, Lung, and Blood Institute/NIH, April 29, 2020.
Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) (NIH)
Discussing the Need for Reliable Antibody Testing for COVID-19
Posted on by Dr. Francis Collins
There’s been a great deal of discussion about whether people who recover from coronavirus disease 2019 (COVID-19), have neutralizing antibodies in their bloodstream to guard against another infection. Lots of interesting data continue to emerge, including a recent preprint from researchers at Sherman Abrams Laboratory, Brooklyn, NY [1]. They tested 11,092 people for antibodies in May at a local urgent care facility and found nearly half had long-lasting IgG antibodies, a sign of exposure to the novel coronavirus SARS-CoV-2, the cause of COVID-19. The researchers also found a direct correlation between the severity of a person’s symptoms and their levels of IgG antibodies.
This study and others remind us of just how essential antibody tests will be going forward to learn more about this challenging pandemic. These assays must have high sensitivity and specificity, meaning there would be few false negatives and false positives, to tell us more about a person’s exposure to SARS-CoV-2. While there are some good tests out there, not all are equally reliable.
Recently, I had a chance to discuss COVID-19 antibody tests, also called serology tests, with Dr. Norman “Ned” Sharpless, Director of NIH’s National Cancer Institute (NCI). Among his many talents, Dr. Sharpless is an expert on antibody testing for COVID-19. You might wonder how NCI got involved in COVID-19 testing. Well, you’re going to find out. Our conversation took place while videoconferencing, with him connecting from North Carolina and me linking in from my home in Maryland. Here’s a condensed transcript of our chat:
Collins: Ned, thanks for joining me. Maybe we should start with the basics. What are antibodies anyway?
Sharpless: Antibodies are proteins that your body makes as part of the learned immune system. It’s the immunity that responds to a bacterium or a virus. In general, if you draw someone’s blood after an infection and test it for the presence of these antibodies, you can often know whether they’ve been infected. Antibodies can hang around for quite a while. How long exactly is a topic of great interest, especially in terms of the COVID-19 pandemic. But we think most people infected with coronavirus will make antibodies at a reasonably high level, or titer, in their peripheral blood within a couple of weeks of the infection.
Collins: What do antibodies tell us about exposure to a virus?
Sharpless: A lot of people with coronavirus are infected without ever knowing it. You can use these antibody assays to try and tell how many people in an area have been infected, that is, you can do a so-called seroprevalence survey.
You could also potentially use these antibody assays to predict someone’s resistance to future infection. If you cleared the infection and established immunity to it, you might be resistant to future infection. That might be very useful information. Maybe you could make a decision about how to go out in the community. So, that part is of intense interest as well, although less scientifically sound at the moment.
Collins: I have a 3D-printed model of SARS-CoV-2 on my desk. It’s sort of a spherical virus that has spike proteins on its surface. Do the antibodies interact with the virus in some specific ways?
Sharpless: Yes, antibodies are shaped like the letter Y. They have two binding domains at the head of each Y that will recognize something about the virus. We find antibodies in the peripheral blood that recognize either the virus nucleocapsid, which is the structural protein on the inside; or the spikes, which stick out and give coronavirus its name. We know now that about 99 percent of people who get infected with the virus will develop antibodies eventually. Most of those antibodies that you can detect to the spike proteins will be neutralizing, which means they can kill the virus in a laboratory experiment. We know from other viruses that, generally, having neutralizing antibodies is a promising sign if you want to be immune to that virus in the future.
Collins: Are COVID-19 antibodies protective? Are there reports of people who’ve gotten better, but then were re-exposed and got sick again?
Sharpless: It’s controversial. People can shed the virus’s nucleic acid [genetic material], for weeks or even more than a month after they get better. So, if they have another nucleic acid test it could be positive, even though they feel better. Often, those people aren’t making a lot of live virus, so it may be that they never stopped shedding the virus. Or it may be that they got re-infected. It’s hard to understand what that means exactly. If you think about how many people worldwide have had COVID-19, the number of legitimate possible reinfection cases is in the order of a handful. So, it’s a pretty rare event, if it happens at all.
Collins: For somebody who does have the antibodies, who apparently was previously infected, do they need to stop worrying about getting exposed? Can they can do whatever they want and stop worrying about distancing and wearing masks?
Sharpless: No, not yet. To use antibodies to predict who’s likely to be immune, you’ve got to know two things.
First: can the tests actually measure antibodies reliably? I think there are assays available to the public that are sufficiently good for asking this question, with an important caveat. If you’re trying to detect something that’s really rare in a population, then any test is going to have limitations. But if you’re trying to detect something that’s more common, as the virus was during the recent outbreak in Manhattan, I think the tests are up to the task.
Second: does the appearance of an antibody in the peripheral blood mean that you’re actually immune or you’re just less likely to get the virus? We don’t know the answer to that yet.
Collins: Let’s be optimistic, because it sounds like there’s some evidence to support the idea that people who develop these antibodies are protected against infection. It also sounds like the tests, at least some of them, are pretty good. But if there is protection, how long would you expect it to last? Is this one of those things where you’re all set for life? Or is this going to be something where somebody’s had it and might get it again two or three years from now, because the immunity faded away?
Sharpless: Since we have no direct experience with this virus over time, it’s hard to answer. The potential for this cell-based humoral immunity to last for a while is there. For some viruses, you have a long-lasting antibody protection after infection; for other viruses, not so much.
So that’s the unknown thing. Is immunity going to last for a while? Of course, if one were to bring up the topic of vaccines, that’s very important to know, because you would want to know how often one would have to give that vaccine, even under optimal circumstances.
Collins: Yes, our conversation about immunity is really relevant to the vaccines we’re trying to develop right now. Will these vaccines be protective for long periods of time? We sure hope so, but we’ve got to look carefully at the issue. Let’s come back, though, to the actual performance of the tests. The NCI has been right in the middle of trying to do this kind of validation. How did that happen, and how did that experience go?
Sharpless: Yes, I think one might ask: why is the National Cancer Institute testing antibody kits for the FDA? It is unusual, but certainly not unheard of, for NCI to take up problems like this during a time of a national emergency. During the HIV era, NCI scientists, along with others, identified the virus and did one of the first successful compound screens to find the drug AZT, one of the first effective anti-HIV therapies.
NCI’s Frederick National Lab also has a really good serology lab that had been predominantly working on human papillomavirus (HPV). When the need arose for serologic testing a few months ago, we pivoted that lab to a coronavirus serology lab. It took us a little while, but eventually we rounded up everything you needed to create positive and negative reference panels for antibody testing.
At that time, the FDA had about 200 manufacturers making serology tests that hoped for approval to sell. The FDA wanted some performance testing of those assays by a dispassionate third party. The Frederick National Lab seemed like the ideal place, and the manufacturers started sending us kits. I think we’ve probably tested on the order of 20 so far. We give those data back to the FDA for regulatory decision making. They’re putting all the data online.
Collins: How did it look? Are these all good tests or were there some clunkers?
Sharpless: There were some clunkers. But we were pleased to see that some of the tests appear to be really good, both in our hands and those of other groups, and have been used in thousands of patients.
There are a few tests that have sensitivities that are pretty high and specificities well over 99 percent. The Roche assay has a 99.8 percent specificity claimed on thousands of patients, and for the Mt. Sinai assay developed and tested by our academic collaborators in a panel of maybe 4,000 patients, they’re not sure they’ve ever had a false positive. So, there are some assays out there that are good.
Collins: There’s been talk about how there will soon be monoclonal antibodies directed against SARS-CoV-2. How are those derived?
Sharpless: They’re picked, generally, for appearing to have neutralizing activity. When a person makes antibodies, they don’t make one antibody to a pathogen. They make a whole family of them. And those can be individually isolated, so you can know which antibodies made by a convalescent individual really have virus-neutralizing capacity. That portion of the antibody that recognizes the virus can be engineered into a manufacturing platform to make monoclonal antibodies. Monoclonal means one kind of antibody. That approach has worked for other infectious diseases and is an interesting idea here too.
Collins: I can say a bit about that, because we are engaged in a partnership with industry and FDA called Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV). One of the hottest ideas right now is monoclonal antibodies, and we’re in the process of devising a master protocol, one for outpatients and one for inpatients.
Janet Woodcock of Operation Warp Speed tells me 21 companies are developing monoclonal antibodies. While doing these trials, we’d love to do comparisons, which is why it’s good to have an organization like ACTIV to bring everybody together, making sure you’re using the same endpoints and the same laboratory measures. I think that, maybe even by late summer, we might have some results. For people who are looking at what’s the next most-hopeful therapeutic option for people who are really sick with COVID-19, so far we have remdesivir. It helps, but it’s not a home run. Maybe monoclonal antibodies will be the next thing that really gives a big boost in survival. That would be the hope.
Ned, let me ask you one final question about herd, or group, immunity. One hears a bit about that in terms of how we are all going to get past this COVID-19 pandemic. What’s that all about?
Sharpless: Herd immunity is when a significant portion of the population is immune to a pathogen, then that pathogen will die out in the population. There just aren’t enough susceptible people left to infect. What the threshold is for herd immunity depends on how infectious the virus is. For a highly infectious virus, like measles, maybe up to 90 percent of the population must be immune to get herd immunity. Whereas for other less-infectious viruses, it may only be 50 percent of the population that needs to be immune to get herd immunity. It’s a theoretical thing that makes some assumptions, such as that everybody’s health status is the same and the population mixes perfectly every day. Neither of those are true.
How well that actual predictive number will work for coronavirus is unknown. The other thing that’s interesting is a lot of that work has been based on vaccines, such as what percentage do you have to vaccinate to get herd immunity? But if you get to herd immunity by having people get infected, so-called natural herd immunity, that may be different. You would imagine the most susceptible people get infected soonest, and so the heterogeneity of the population might change the threshold calculation.
The short answer is nobody wants to find out. No one wants to get to herd immunity for COVID-19 through natural herd immunity. The way you’d like to get there is with a vaccine that you then could apply to a large portion of the population, and have them acquire immunity in a more safe and controlled manner. Should we have an efficacious vaccine, this question will loom large: how many people do we need to vaccinate to really try and protect vulnerable populations?
Collins: That’s going to be a really critical question for the coming months, as the first large-scale vaccine trials get underway in July, and we start to see how they work and how successful and safe they are. But I’m also worried seeing some reports that 1 out of 5 Americans say they wouldn’t take a vaccine. It would be truly a tragedy if we have a safe and effective vaccine, but we don’t get enough uptake to achieve herd immunity. So, we’ve got some work to do on all fronts, that’s for sure.
Ned, I want to thank you for sharing all this information about antibodies and serologies and other things, as well as thank you for your hard work with all your amazing NCI colleagues.
Sharpless: Thanks for having me.
Reference:
[1] SARS-CoV-2 IgG Antibody Responses in New York City. Reifer J, Hayum N, Heszkel B, Klagsbald I, Streva VA. medRxiv. Preprint posted May 26, 2020.
Links:
Coronavirus (COVID-19) (NIH)
At NCI, A Robust and Rapid Response to the COVID-19 Pandemic. Norman E. Sharpless. Cancer Currents Blog. April 17, 2020 (National Cancer Institute/NIH)
Serological Testing for SARS-CoV-2 Antibodies (American Medical Association, Chicago)
COVID-19 Antibody Testing Primer (Infectious Diseases Society of America, Arlington, VA)
Accelerating COVID-19 Therapeutic Interventions and Vaccines (NIH)
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