Posted on by Dr. Francis Collins
The recent COVID-19 outbreak of a novel type of coronavirus that began in China has prompted a massive global effort to contain and slow its spread. Despite those efforts, over the last month the virus has begun circulating outside of China in multiple countries and territories.
Cases have now appeared in the United States involving some affected individuals who haven’t traveled recently outside the country. They also have had no known contact with others who have recently arrived from China or other countries where the virus is spreading. The NIH and other U.S. public health agencies stand on high alert and have mobilized needed resources to help not only in its containment, but in the development of life-saving interventions.
On the treatment and prevention front, some encouraging news was recently reported. In record time, an NIH-funded team of researchers has created the first atomic-scale map of a promising protein target for vaccine development . This is the so-called spike protein on the new coronavirus that causes COVID-19. As shown above, a portion of this spiky surface appendage (green) allows the virus to bind a receptor on human cells, causing other portions of the spike to fuse the viral and human cell membranes. This process is needed for the virus to gain entry into cells and infect them.
Preclinical studies in mice of a candidate vaccine based on this spike protein are already underway at NIH’s Vaccine Research Center (VRC), part of the National Institute of Allergy and Infectious Diseases (NIAID). An early-stage phase I clinical trial of this vaccine in people is expected to begin within weeks. But there will be many more steps after that to test safety and efficacy, and then to scale up to produce millions of doses. Even though this timetable will potentially break all previous speed records, a safe and effective vaccine will take at least another year to be ready for widespread deployment.
Coronaviruses are a large family of viruses, including some that cause “the common cold” in healthy humans. In fact, these viruses are found throughout the world and account for up to 30 percent of upper respiratory tract infections in adults.
This outbreak of COVID-19 marks the third time in recent years that a coronavirus has emerged to cause severe disease and death in some people. Earlier coronavirus outbreaks included SARS (severe acute respiratory syndrome), which emerged in late 2002 and disappeared two years later, and MERS (Middle East respiratory syndrome), which emerged in 2012 and continues to affect people in small numbers.
Soon after COVID-19 emerged, the new coronavirus, which is closely related to SARS, was recognized as its cause. NIH-funded researchers including Jason McLellan, an alumnus of the VRC and now at The University of Texas at Austin, were ready. They’d been studying coronaviruses in collaboration with NIAID investigators for years, with special attention to the spike proteins.
Just two weeks after Chinese scientists reported the first genome sequence of the virus , McLellan and his colleagues designed and produced samples of its spike protein. Importantly, his team had earlier developed a method to lock coronavirus spike proteins into a shape that makes them both easier to analyze structurally via the high-resolution imaging tool cryo-electron microscopy and to use in vaccine development efforts.
After locking the spike protein in the shape it takes before fusing with a human cell to infect it, the researchers reconstructed its atomic-scale 3D structural map in just 12 days. Their results, published in Science, confirm that the spike protein on the virus that causes COVID-19 is quite similar to that of its close relative, the SARS virus. It also appears to bind human cells more tightly than the SARS virus, which may help to explain why the new coronavirus appears to spread more easily from person to person, mainly by respiratory transmission.
McLellan’s team and his NIAID VRC counterparts also plan to use the stabilized spike protein as a probe to isolate naturally produced antibodies from people who’ve recovered from COVID-19. Such antibodies might form the basis of a treatment for people who’ve been exposed to the virus, such as health care workers.
The NIAID is now working with the biotechnology company Moderna, Cambridge, MA, to use the latest findings to develop a vaccine candidate using messenger RNA (mRNA), molecules that serve as templates for making proteins. The goal is to direct the body to produce a spike protein in such a way to elicit an immune response and the production of antibodies. An early clinical trial of the vaccine in people is expected to begin in the coming weeks. Other vaccine candidates are also in preclinical development.
Meanwhile, the first clinical trial in the U.S. to evaluate an experimental treatment for COVID-19 is already underway at the University of Nebraska Medical Center’s biocontainment unit . The NIH-sponsored trial will evaluate the safety and efficacy of the experimental antiviral drug remdesivir in hospitalized adults diagnosed with COVID-19. The first participant is an American who was repatriated after being quarantined on the Diamond Princess cruise ship in Japan.
As noted, the risk of contracting COVID-19 in the United States is currently low, but the situation is changing rapidly. One of the features that makes the virus so challenging to stay in front of is its long latency period before the characteristic flu-like fever, cough, and shortness of breath manifest. In fact, people infected with the virus may not show any symptoms for up to two weeks, allowing them to pass it on to others in the meantime. You can track the reported cases in the United States on the Centers for Disease Control and Prevention’s website.
As the outbreak continues over the coming weeks and months, you can be certain that NIH and other U.S. public health organizations are working at full speed to understand this virus and to develop better diagnostics, treatments, and vaccines.
 Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation. Wrapp D, Wang N, Corbett KS, Goldsmith JA, Hsieh CL, Abiona O, Graham BS, McLellan JS. Science. 2020 Feb 19.
 A new coronavirus associated with human respiratory disease in China. Wu F, Zhao S, Yu B, Chen YM, Wang W, Song ZG, Hu Y, Tao ZW, Tian JH, Pei YY, Yuan ML, Zhang YL, Dai FH, Liu Y, Wang QM, Zheng JJ, Xu L, Holmes EC, Zhang YZ. Nature. 2020 Feb 3.
 NIH clinical trial of remdesivir to treat COVID-19 begins. NIH News Release. Feb 25, 2020.
Coronaviruses (National Institute of Allergy and Infectious Diseases/NIH)
Coronavirus (COVID-19) (NIAID)
Coronavirus Disease 2019 (Centers for Disease Control and Prevention, Atlanta)
NIH Support: National Institute of Allergy and Infectious Diseases
Posted on by Dr. Francis Collins
As a kid who was home-schooled on a Virginia farm in the 1950s, I wasn’t around other kids very much, and so didn’t get exposed to measles. And there was no vaccine yet. Later on as a medical resident, I didn’t recognize that I wasn’t immune. So when I was hospitalized with a severe febrile illness at age 29, it took a while to figure out the diagnosis. Yes, it was measles. I have never been that sick before or since. I was lucky not to have long-term consequences, and now I’m learning that there may be even more to consider.
With the big push to get kids vaccinated, you’ve probably heard about some of the very serious complications of measles: hearing-threatening ear infections, bronchitis, laryngitis, and even life-threatening forms of pneumonia and encephalitis. But now comes word of yet another way in which the measles can be devastating—one that may also have long-term consequences for a person’s health.
In a new study in the journal Science, a research team, partly funded by NIH, found that the measles virus not only can make children deathly ill, it can cause their immune systems to forget how to ward off other common infections . The virus does this by wiping out up to nearly three-quarters of the protective antibodies that a child’s body has formed in response to past microbial invaders and vaccinations. This immune “amnesia” can leave a child more vulnerable to re-contracting infections, such as influenza or respiratory syncytial virus (RSV), that they may have been protected against before they came down with measles.
The finding comes as yet another reason to feel immensely grateful that, thanks to our highly effective vaccination programs, most people born in the U.S. from the 1960s onward should never have to experience the measles.
There had been hints that the measles virus might somehow suppress a person’s immune system. Epidemiological evidence also had suggested that measles infections might lead to increased susceptibility to infection for years afterwards . Scientists had even suspected this might be explained by a kind of immune amnesia. The trouble was that there wasn’t any direct proof that such a phenomenon actually existed.
In the new work, the researchers, led by Michael Mina, Tomasz Kula, and Stephen Elledge, Howard Hughes Medical Institute and Brigham and Women’s Hospital, Boston, took advantage of a tool developed a few years ago in the Elledge lab called VirScan . VirScan detects antibodies in blood samples acquired as a result of a person’s past encounters with hundreds of viruses, bacteria, or vaccines, providing a comprehensive snapshot of acquired immunity at a particular moment in time.
To look for evidence of immune amnesia following the measles, the research team needed blood samples gathered from people both before and after infection. These types of samples are currently hard to come by in the U.S. thanks to the success of vaccines. By partnering with Rik de Swart, Erasmus University Medical Center, Rotterdam, Netherlands, they found the samples that they needed.
During a recent measles outbreak in the Netherlands, de Swart had gathered blood samples from children living in communities with low vaccination rates. Elledge’s group used VirScan with 77 unvaccinated kids to measure antibodies in samples collected before and about two months after their measles infections.
That included 34 children who had mild infections and 43 who had severe measles. The researchers also examined blood samples from five children who remained uninfected and 110 kids who hadn’t been exposed to the measles virus.
The VirScan data showed that the infected kids, not surprisingly, produced antibodies to the measles virus. But their other antibodies dropped and seemed to be disappearing. In fact, depending on the severity of measles infection, the kids showed on average a loss of around 40 percent of their antibody memory, with greater losses in children with severe cases of the measles. In at least one case, the loss reached a whopping 73 percent.
This all resonates with me. I do recall that after my bout with the measles, I seemed to be coming down with a lot of respiratory infections. I attributed that to the lifestyle of a medical resident—being around lots of sick patients and not getting much sleep. But maybe it was more than that.
The researchers suggest that the loss of immune memory may stem from the measles virus destroying some of the long-lived cells in bone marrow. These cells remember past infections and, based on that immunological memory, churn out needed antibodies to thwart reinvading viruses.
Interestingly, after a measles infection, the children’s immune systems still responded to new infections and could form new immune memories. But it appears the measles caused long term, possibly permanent, losses of a significant portion of previously acquired immunities. This loss of immune memory put the children at a distinct disadvantage should those old bugs circulate again.
It’s important to note that, unlike measles infection, the MMR (measles, mumps, rubella) vaccine does NOT compromise previously acquired immunity. So, these findings come as yet another reminder of the public value of measles vaccination.
Prior to 1963, when the measles vaccine was developed, 3 to 4 million Americans got the measles each year. As more people were vaccinated, the incidence of measles plummeted. By the year 2000, the disease was declared eliminated from the U.S.
Unfortunately, measles has made a come back, fueled by vaccine refusals. In October, the Centers for Disease Control and Prevention (CDC) reported an estimated 1,250 measles cases in the United States so far in 2019, surpassing the total number of cases reported annually in each of the past 25 years .
Around the world, measles continues to infect 7 million people each year, leading to an estimated 120,000 deaths. Based on the new findings, Elledge’s team now suspects the actual toll of the measles may be five times greater, due to the effects of immune amnesia.
The good news is those numbers can be reduced if more people get the vaccine, which has been shown repeatedly in many large and rigorous studies to be safe and effective. The CDC recommends that children should receive their first dose by 12 to 15 months of age and a second dose between the ages of 4 and 6. Older people who’ve been vaccinated or have had the measles previously should consider being re-vaccinated, especially if they live in places with low vaccination rates or will be traveling to countries where measles are endemic.
 Measles virus infection diminishes preexisting antibodies that offer protection from other pathogens. Mina MJ, Kula T, Leng Y, Li M, de Vries RD, Knip M, Siljander H, Rewers M, Choy DF, Wilson MS, Larman HB, Nelson AN, Griffin DE, de Swart RL, Elledge SJ. et al. Science. 2019 Nov 1; 366 (6465): 599-606.
 Long-term measles-induced immunomodulation increases overall childhood infectious disease mortality. Mina MJ, Metcalf CJE, De Swart RL, Osterhaus ADME, Grenfell BT. Science. 2015 May 8; 348(6235).
 Viral immunology. Comprehensive serological profiling of human populations using a synthetic human virome. Xu GJ, Kula T, Xu Q, Li MZ, Vernon SD, Ndung’u T, Ruxrungtham K, Sanchez J, Brander C, Chung RT, O’Connor KC, Walker B, Larman HB, Elledge SJ. Science. 2015 Jun 5;348(6239):aaa0698.
 Measles cases and outbreaks. Centers for Disease Control and Prevention. Oct. 11, 2019.
Measles (MedlinePlus Medical Encyclopedia/National Library of Medicine/NIH)
Measles History (Centers for Disease Control and Prevention)
Vaccines (National Institute of Allergy and Infectious Diseases/NIAID)
Vaccines Protect Your Community (Vaccines.gov)
Elledge Lab (Harvard Medical School, Boston)
NIH Support: National Institute of Allergy and Infectious Diseases; National Institute of Diabetes and Digestive and Kidney Diseases
Posted on by Dr. Francis Collins
It’s an inescapable conclusion from the book of Ecclesiastes that’s become part of popular culture thanks to folk legends Pete Seeger and The Byrds: “To everything (turn, turn, turn), there is a season.” That’s certainly true of viral outbreaks, from the flu-causing influenza virus peaking each year in the winter to polio outbreaks often rising in the summer. What fascinates Micaela Martinez is, while those seasonal patterns of infection have been recognized for decades, nobody really knows why they occur.
Martinez, an infectious disease ecologist at Princeton University, Princeton, NJ, thinks colder weather conditions and the tendency for humans to stay together indoors in winter surely play a role. But she also thinks an important part of the answer might be found in a place most hadn’t thought to look: seasonal changes in the human immune system. Martinez recently received an NIH Director’s 2016 Early Independence Award to explore fluctuations in the body’s biological rhythms over the course of the year and their potential influence on our health.