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COVID-19 testing

New Metric Identifies Coronavirus Hotspots in Real Time

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High viral load found from PCR helps to predict hotspots

During the pandemic, it’s been critical to track in real time where the coronavirus is spreading at home and abroad. But it’s often hard for public health officials to know whether changes in the reported number of COVID-19 cases over time truly reflect the spread of the virus or whether they are confounded by changes in testing levels or lags in the reporting of results.

Now, NIH-funded researchers have discovered a clever workaround to detect more accurately where COVID-19 hotspots are emerging. As published in the journal Science, the new approach focuses on the actual amount of virus present in a positive COVID diagnostic test [1], not just whether the test is positive or negative. What’s even better is these data on a person’s “viral load” are readily available from polymerase chain reaction, or PCR, tests that are the “gold standard” for detecting SARS-CoV-2, the virus responsible for COVID-19. In fact, if you’ve been tested for COVID-19, there’s a good chance you’ve had a PCR-based test.

Here’s how a PCR test for COVID-19 works. After a person provides a nasal swab or saliva sample, any genetic material in the sample is extracted and prepared for the PCR machine. It uses special nucleic acid primers that, if any genetic material from SARS-CoV-2 is present, will make millions more copies of them and result in a positive test result. PCR is an enzymatic reaction that works by running many cycles of heating and cooling; each cycle results in doubling of the genetic material present in the original sample.

But it turns out that PCR can go beyond a simple “yes” or “no” test result. It’s also possible to get some sense of how much coronavirus is present in a positive sample based on the number of cycles required to make enough copies of its genetic material to get the “yes” result. This measure is known as the “cycle threshold,” or Ct, value.

When a sample is run with lots of virus in it, the PCR machine doesn’t need to make so many cycles to reach detectable levels—and the Ct value is considered low. But, when the virus is barely present in a sample, the machine needs to run more cycles before it will reach the threshold for detection. In this case, the Ct value is high. This makes the Ct metric a bit counterintuitive: low Ct means a high level of infection, and high Ct means a low level of infection.

In the new study, researchers in Michael Mina’s lab, Harvard T. H. Chan School of Public Health, Boston, including James Hay and Lee Kennedy-Shaffer, wanted to use Ct values to understand better the overall trajectory of the spread of SARS-CoV-2. Their idea was a little out of the box, since Ct values weren’t being factored into a diagnostic testing process that was set up to give people a yes-or-no answer about COVID-19 status. In fact, Ct values were often discarded.

The team members had a hunch that the amount of virus in patient samples would vary based on whether an outbreak is increasing or declining. Their reasoning was that during an outbreak, when SARS-CoV-2 is spreading rapidly through a community, a larger proportion of infected individuals will have recently contracted the virus than when it is spreading more slowly. The researchers also knew that the virus reaches its peak level in humans soon after infection (generally a couple of days before symptoms begin), and then falls to very low but still detectable levels over the course of weeks or sometimes even months. So, when viral load within samples is highest—and Ct values are lowest—it suggests an outbreak of SARS-CoV-2 is underway. As an outbreak slows and cases fall, viral loads should fall and Ct values rise.

The researchers found that just 30 positive PCR test results on a single day were enough to give an accurate real-time estimate of the growth rate of SARS-CoV-2 infections based on Ct values. With Ct values from multiple time points, it was possible to reconstruct the epidemic curve and estimate the true number of people infected. They found that even Ct values collected from a single location at a single point in time could provide extremely valuable information about the growth or decline of an outbreak.

The findings suggest that these data can now be captured and put to good use as a key metric for decision-making and gauging the success of the pandemic response going forward. It’s also important to note that the value of these data are not unique to COVID-19 and the ongoing pandemic. It appears this can be extremely useful new way to monitor the course of other viral outbreaks, now and in the future, in a way that’s less susceptible to the vagaries of testing. The hope is that this will mean even greater success in capturing viral outbreaks and mobilizing resources in real time to the places where they are most needed.

Reference:

[1] Estimating epidemiologic dynamics from cross-sectional viral load distributions. Hay JA, Kennedy-Shaffer L, Kanjilal S, Lennon NJ, Gabriel SB, Lipsitch M, Mina MJ. Science. 2021 Jun 3.

Links:

COVID-19 Research (NIH)

Michael Mina (Harvard T. H. Chan School of Public Health, Boston)

NIH Support: Common Fund, National Institute of General Medical Sciences; National Cancer Institute


New Initiative Puts At-Home Testing to Work in the Fight Against COVID-19

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COVID-19 Update: Community At-Home Testing
Credit: nito/Shutterstock

Thankfully COVID-19 testing is now more widely available than it was earlier in the pandemic. But getting tested often still involves going to a doctor’s office or community testing site and waiting as long as a couple of days for the results. Testing would be so much easier if people could do it themselves at home. If the result came up positive, a person could immediately self-isolate, helping to stop the coronavirus that causes COVID-19, SARS-CoV-2, from spreading any further in their communities.

That’s why I’m happy to report that the Centers for Disease Control and Prevention (CDC), in close collaboration with state and local public health departments and with NIH, has begun an innovative community health initiative called “Say Yes! COVID Test.” The initiative, the first large-scale evaluation of community-wide, self-administered COVID-19 testing, was launched last week in Pitt County, NC, and will start soon in Chattanooga/Hamilton County, TN.

The initiative will provide as many as 160,000 residents in these two locales with free access to rapid COVID-19 home tests, supplied through NIH’s Rapid Acceleration of Diagnostics (RADx) initiative. Participants can administer these easy-to-use tests themselves up to three times a week for one month. The goal is to assess the benefits of self-administered COVID-19 testing and help guide other communities in implementing similar future programs to slow the spread of COVID-19.

The counties in North Carolina and Tennessee were selected based on several criteria. These included local infection rates; public availability of accurate COVID-19 tracking data, such as that gathered by wastewater surveillance; the presence of local infrastructure needed to support the project; and existing community relationships through RADx’s Underserved Populations (RADx-UP) program. Taken together, these criteria also help to ensure that vulnerable and underserved populations will benefit from the initiative.

The test is called the QuickVue At-Home COVID-19 Test. Developed with RADx support by San Diego-based diagnostic company Quidel, this test is easily performed with a nasal swab and offers results in just 10 minutes. Last week, the test was among several authorized by the Food and Drug Administration (FDA) for over-the-counter use to screen for COVID-19 at home.

Participants can order their QuickVue test kits online for home delivery or local pick up. A free online tool, which was developed with NIH support by CareEvolution, LLC, Ann Arbor, MI, will also be available to provide testing instructions, help in understanding test results, and text message reminders about testing. This innovative tool is also available as a smartphone app.

A recent study, supported by the RADx initiative, found that rapid antigen testing for COVID-19, when conducted at least three times per week, achieves a viral detection level on par with the gold standard of PCR-based COVID-19 testing processed in a lab [1]. That’s especially significant considering the other advantages of a low-cost, self-administered rapid test, including confidential results at home in minutes.

The Say Yes! COVID Test initiative is an important next step in informing the best testing strategies in communities all over the country to end this and future pandemics. The initiative will also help to determine how readily people accept such testing when it’s made available to them. If the foundational data looks promising, the hope is that rapid at-home tests will help to encourage people to protect themselves and others by following the three W’s (Wear a mask. Wash your hands. Watch your distance), getting vaccinated, and saying “Yes” to the COVID-19 test.

Reference:

[1] Longitudinal assessment of diagnostic test performance over the course of acute SARS-CoV-2 infection. Smith RL, Gibson LL, Martinez PP, Heetderks WJ, McManus DD, Brooke CB, et al. medRxiv, 2021 March 20.

Links:

CDC and NIH bring COVID-19 self-testing to residents in two locales, NIH News Release, March 31, 2021

Say Yes! COVID Test

Rapid Acceleration of Diagnostics (RADx) (NIH)

COVID-19 Testing (CDC)

Quidel Corporation (San Diego, CA)

Coronavirus (COVID-19) Update: FDA Continues to Advance Over-the Counter and Other Screening Test Development, FDA News Release, March 31, 2021

NIH Support: National Heart, Lung, and Blood Institute; National Institute of Biomedical Imaging and Bioengineering


First Anniversary of NIH’s COVID-19 Testing Car Line

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I joined approximately 80 volunteers to mark the one-year anniversary of NIH’s COVID-19 Testing Car Line. The event was held at NIH’s Gateway entrance on March 17. Pictured here with me are some of the awesome volunteers, from various NIH institutes, centers, and offices, who have helped out in many ways and at many times throughout the year to test staff who report symptoms of COVID-19. Here are some fun facts from the line: First tests performed: March 18, 2020; Coldest Day: 25 degrees on January 29, 2021; Hottest Day: 99 degrees on July 20, 2020; Distinct Staff Tested: 5,291; Total Samples Taken: 7,797; Total Carline Positives: 502. Credit: NIH


Citizen Scientists Take on the Challenge of Long-Haul COVID-19

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Woman frustrated while working
Credit: iStock/Poike

Coronaviruses are a frequent cause of the common cold. Most of us bounce back from colds without any lasting health effects. So, you might think that individuals who survive other infectious diseases caused by coronaviruses—including COVID-19—would also return to normal relatively quickly. While that can be the case for some people, others who’ve survived even relatively mild COVID-19 are experiencing health challenges that may last for weeks or even months. In fact, the situation is so common, that some of these folks have banded together and given their condition a name: the COVID “long-haulers.”

Among the many longer-term health problems that have been associated with COVID-19 are shortness of breath, fatigue, cognitive issues, erratic heartbeat, gastrointestinal issues, low-grade fever, intolerance to physical or mental activity, and muscle and joint pains. COVID-19 survivors report that these symptoms flair up unpredictably, often in different combinations, and can be debilitating for days and weeks at a time. Because COVID-19 is such a new disease, little is known about what causes the persistence of symptoms, what is impeding full recovery, or how to help the long-haulers.

More information is now emerging from the first detailed patient survey of post-COVID syndrome, also known as Long COVID [1]. What’s unique about the survey is that it has been issued by a group of individuals who are struggling with the syndrome themselves. These citizen scientists, who belong to the online Body Politic COVID-19 Support Group, decided to take matters into their own hands. They already had a pretty good grip on what sort of questions to ask, as well as online access to hundreds of long-haulers to whom they could pose the questions.

The citizen scientists’ group, known as the Patient-led Research for COVID-19, brought a lot of talent and creativity to the table. Members reside in the United States, Canada, and England, and none have ever met face to face. But, between their day jobs, managing time differences, and health challenges, each team member spends about 20 hours per week working on their patient-led research, and are now putting the final touches on a follow-up survey that will get underway in the next few weeks.

For their first survey, the group members faced the difficult decision of whom to contact. First, they needed to define long hauler. For that, they decided to target people whose symptoms persisted for more than 2 weeks after their initial recovery from COVID-19. The 640 individuals who responded to the survey were predominately white females between the ages of 30 to 49 who lived in the United States. The members said that the gender bias may stem from women being more likely to join support groups and complete surveys, though there may be a gender component to Long COVID as well. About 10 percent of respondents reported that they had ultimately recovered from this post-COVID syndrome.

Another important issue revolved around COVID-19 testing. Most long-haulers in the online group had gotten sick in March and April, but weren’t so sick that they needed to be hospitalized. Because COVID-19 testing during those months was often limited to people hospitalized with severe respiratory problems, many long-haulers with mild or moderate COVID-like symptoms weren’t tested. Others were tested relatively late in the course of their illness, which can increase the likelihood of false negatives.

The team opted to cast a wide investigative net, concluding that limiting its data to only people who tested positive for COVID-19 might lead to the loss of essential information on long-haulers. It turns out that half of the respondents hadn’t been tested for SARS-CoV-2, the virus that causes COVID-19. The other half was divided almost equally between those who tested positive and those who tested negative. Here are some highlights of the survey’s findings:

Top 10 Symptoms: Respondents were asked to rank their most common symptoms and their relative severity. From highest to lowest, they were: mild shortness of breath, mild tightness of chest, moderate fatigue, mild fatigue, chills or sweats, mild body aches, dry cough, elevated temperature (98.8-100), mild headache, and brain fog/concentration challenges. Highlighting the value of patient-led research, the team was able to assemble an initial list of 62 symptoms that long-haulers often discuss in support groups. The survey revealed common symptoms that have been greatly underreported in the media, such as neurological symptoms. These include brain fog, concentration challenges, and dizziness.

Making a Recovery: Of the 60 respondents who had recovered, the average time to recovery was 27 days. The respondents who had not recovered had managed their symptoms for 40 days on average, with most dealing with health problems for 5 to 7 weeks. The report shows that the chance of full recovery by day 50 is less than 20 percent.

Exercise Capacity: About 65 percent of respondents now consider themselves mostly sedentary. Most had been highly physically active before developing COVID-19. Many long-haulers expressed concern that overexertion causes relapses

Testing. Respondents who reported testing positive for SARS-CoV-2 were tested on average earlier in their illness (by day 10) than those who reported testing negative (by day 16). The team noted that their findings parallel those in a recent published scientific study, which found false-negative rates for current PCR-based assays rose as the time between SARS-CoV-2 infection and testing increased [2]. In that published study, by day 21, the false-negative rate reached 66 percent. Only two symptoms (loss of smell and loss of taste) occurred more frequently in respondents who tested positive; the other 60 symptoms were statistically the same between groups. The citizen scientists speculate that testing is not capturing a subset of COVID patients, and more investigation is required.

Since issuing their survey results on May 11, the team has met with staff from the Centers for Disease Control and Prevention and the World Health Organization. Their work also been mentioned in magazine articles and even cited in some papers published in scientific journals.

In their next survey, these citizen scientists hope to fill in gaps in their first report, including examining antibody testing results, neurological symptoms, and the role of mental health. To increase geographic and demographic diversity, they will also translate the survey into 10 languages. If you’re a COVID-19 long-hauler and would like to find out how to get involved, there’s still time to take part in the next survey.

References:

[1] “What Does COVID-19 Recovery Actually Look Like?” Patient-led Research for COVID-19. May 11, 2020.

[2] Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction-Based SARS-CoV-2 Tests by Time Since Exposure. Kucirka LM, Lauer SA, Laeyendecker O, Boon D, Lessler J. Ann Intern Med. 2020 Aug 18;173(4):262-267.

Links:

Coronavirus (COVID-19) (NIH)

Patient-led Research for COVID-19


Charting a Rapid Course Toward Better COVID-19 Tests and Treatments

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Point of care anti
Credit: Quidel; iStock/xavierarnau

It is becoming apparent that our country is entering a new and troubling phase of the pandemic as SARS-CoV-2, the novel coronavirus that causes COVID-19, continues to spread across many states and reaches into both urban and rural communities. This growing community spread is hard to track because up to 40 percent of infected people seem to have no symptoms. They can pass the virus quickly and unsuspectingly to friends and family members who might be more vulnerable to becoming seriously ill. That’s why we should all be wearing masks when we go out of the house—none of us can be sure we’re not that asymptomatic carrier of the virus.

This new phase makes fast, accessible, affordable diagnostic testing a critical first step in helping people and communities. In recognition of this need, NIH’s Rapid Acceleration of Diagnostics (RADx) initiative, just initiated in late April, has issued an urgent call to the nation’s inventors and innovators to develop fast, easy-to-use tests for SARS-CoV-2, the novel coronavirus that causes COVID-19. It brought a tremendous response, and NIH selected about 100 of the best concepts for an intense one-week “shark-tank” technology evaluation process.

Moving ahead at an unprecedented pace, NIH last week announced the first RADx projects to come through the deep dive with flying colors and enter the scale-up process necessary to provide additional rapid testing capacity to the U.S. public. As part of the RADx initiative, seven biomedical technology companies will receive a total of $248.7 million in federal stimulus funding to accelerate their efforts to scale up new lab-based and point-of-care technologies.

Four of these projects will aim to bolster the nation’s lab-based COVID-19 diagnostics capacity by tens of thousands of tests per day as soon as September and by millions by the end of the year. The other three will expand point-of-care testing for COVID-19, making results more rapidly and readily available in doctor’s offices, urgent care clinics, long-term care facilities, schools, child care centers, or even at home.

This is only a start, and we expect that more RADx projects will advance in the coming months and begin scaling up for wide-scale use. In the meantime, here’s an overview of the first seven projects developed through the initiative, which NIH is carrying out in partnership with the Office of the Assistant Secretary of Health, the Biomedical Advanced Research and Development Authority, and the Department of Defense:

Point-of-Care Testing Approaches

Mesa Biotech. Hand-held testing device detects the genetic material of SARS-CoV-2. Results are read from a removable, single-use cartridge in 30 minutes.

Quidel. Test kit detects protein (viral antigen) from SARS-CoV-2. Electronic analyzers provide results within 15 minutes. The U.S. Department of Health and Human Service has identified this technology for possible use in nursing homes.

Talis Biomedical. Compact testing instrument uses a multiplexed cartridge to detect the genetic material of SARS-CoV-2 through isothermal amplification. Optical detection system delivers results in under 30 minutes.

Lab-based Testing Approaches

Ginkgo Bioworks. Automated system uses next-generation sequencing to scan patient samples for SARS-CoV-2’s genetic material. This system will be scaled up to make it possible to process tens of thousands of tests simultaneously and deliver results within one to two days. The company’s goal is to scale up to 50,000 tests per day in September and 100,000 per day by the end of 2020.

Helix OpCo. By combining bulk shipping of test kits and patient samples, automation, and next-generation sequencing of genetic material, the company’s goal is to process up to 50,000 samples per day by the end of September and 100,000 per day by the end of 2020.

Fluidigm. Microfluidics platform with the capacity to process thousands of polymerase chain reaction (PCR) tests for SARS-CoV-2 genetic material per day. The company’s goal is to scale up this platform and deploy advanced integrated fluidic chips to provide tens to hundreds of thousands of new tests per day in the fall of 2020. Most tests will use saliva.

Mammoth Biosciences. System uses innovative CRISPR gene-editing technology to detect key pieces of SARS-CoV-2 genetic material in patient samples. The company’s goal is to provide a multi-fold increase in testing capacity in commercial laboratories.

At the same time, on the treatment front, significant strides continue to be made by a remarkable public-private partnership called Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV). Since its formation in May, the partnership, which involves 20 biopharmaceutical companies, academic experts, and multiple federal agencies, has evaluated hundreds of therapeutic agents with potential application for COVID-19 and prioritized the most promising candidates.

Among the most exciting approaches are monoclonal antibodies (mAbs), which are biologic drugs derived from neutralizing antibodies isolated from people who’ve survived COVID-19. This week, the partnership launched two trials (one for COVID-19 inpatients, the other for COVID-19 outpatients) of a mAB called LY-CoV555, which was developed by Eli Lilly and Company, Indianapolis, IN. It was discovered by Lilly’s development partner AbCellera Biologics Inc. Vancouver, Canada, in collaboration with the NIH’s National Institute of Allergy and Infectious Diseases (NIAID). In addition to the support from ACTIV, both of the newly launched studies also receive support for Operation Warp Speed, the government’s multi-agency effort against COVID-19.

LY-CoV555 was derived from the immune cells of one of the very first survivors of COVID-19 in the United States. It targets the spike protein on the surface of SARS-CoV-2, blocking it from attaching to human cells.

The first trial, which will look at both the safety and efficacy of the mAb for treating COVID-19, will involve about 300 individuals with mild to moderate COVID-19 who are hospitalized at facilities that are part of existing clinical trial networks. These volunteers will receive either an intravenous infusion of LY-CoV555 or a placebo solution. Five days later, their condition will be evaluated. If the initial data indicate that LY-CoV555 is safe and effective, the trial will transition immediately—and seamlessly—to enrolling an additional 700 participants with COVID-19, including some who are severely ill.

The second trial, which will evaluate how LY-CoV555 affects the early course of COVID-19, will involve 220 individuals with mild to moderate COVID-19 who don’t need to be hospitalized. In this study, participants will randomly receive either an intravenous infusion of LY-CoV555 or a placebo solution, and will be carefully monitored over the next 28 days. If the data indicate that LY-CoV555 is safe and shortens the course of COVID-19, the trial will then enroll an additional 1,780 outpatient volunteers and transition to a study that will more broadly evaluate its effectiveness.

Both trials are later expected to expand to include other experimental therapies under the same master study protocol. Master protocols allow coordinated and efficient evaluation of multiple investigational agents at multiple sites as the agents become available. These protocols are designed with a flexible, rapidly responsive framework to identify interventions that work, while reducing administrative burden and cost.

In addition, Lilly this week started a separate large-scale safety and efficacy trial to see if LY-CoV555 can be used to prevent COVID-19 in high-risk residents and staff at long-term care facilities. The study isn’t part of ACTIV.

NIH-funded researchers have been extremely busy over the past seven months, pursuing every avenue we can to detect, treat, and, ultimately, end this devasting pandemic. Far more work remains to be done, but as RADx and ACTIV exemplify, we’re making rapid progress through collaboration and a strong, sustained investment in scientific innovation.

Links:

Coronavirus (COVID-19) (NIH)

Rapid Acceleration of Diagnostics (RADx)

Video: NIH RADx Delivering New COVID-19 Testing Technologies to Meet U.S. Demand (YouTube)

Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV)

Explaining Operation Warp Speed (U.S. Department of Health and Human Resources/Washington, D.C.)

NIH delivering new COVID-19 testing technologies to meet U.S. demand,” NIH news release,” July 31, 2020.

NIH launches clinical trial to test antibody treatment in hospitalized COVID-19 patients,” NIH new release, August 4, 2020.

NIH clinical trial to test antibodies and other experimental therapeutics for mild and moderate COVID-19,” NIH news release, August 4, 2020.


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