National Institutes of Health All of Us Research Program

Antibody Testing for COVID-19 Research

Researchers want to learn more about when and where COVID-19 first spread in the United States and how new antibody tests perform and can be used in such research.

People who join All of Us give the program permission to do research on the samples and data they share. So when the COVID-19 pandemic began, the program already had thousands of samples on hand. And because of this, we were able to help with this important research.

All of Us tested blood samples collected during the time when the virus first started to appear in the U.S. The tests looked for antibodies against the virus that causes COVID-19. The results may help researchers learn more about the virus, its spread, and its impact.

We are grateful to our participants for making this study possible!

How Antibody Testing Works

Antibody tests are not the same as the test that checks to see if you currently are infected with the virus that causes COVID-19. Instead of using a swab that goes in your nose or throat or a saliva sample, antibody tests use blood samples. Antibody tests do not check whether you have the virus now. Instead, they can show whether you had the virus in the past. This can be useful in finding past infections, because some people who get the new coronavirus never have symptoms.

Your immune system makes antibodies in response to a virus or bacteria to help your body fight an infection. Our test looked for a type of antibody called Immunoglobulin G (IgG). IgG appears about 1–3 weeks after contracting the virus and stays in the blood for a while. Scientists do not know for sure how long IgG antibodies against the new coronavirus stay in the blood. They also do not know whether, or how long, these antibodies can protect someone from getting infected again. Still, we can look in a person’s blood for the presence of IgG antibodies that the body produced to combat the new coronavirus. If we find them, we know that person was likely infected.

Antibody against SARS-CoV-2

Serology, or antibody testing, checks a sample of a person’s blood to look for antibodies against SARS-CoV-2, the virus that causes COVID-19.

Antibodies usually become detectable in the blood 1–3 weeks after someone is infected.

Person becomes infected

1-3 weeks

Person has detectable level of antibodies*

*Some people may take longer than 3 weeks to develop antibodies, and some people may not develop antibodies.

A positive result from this test may mean that a person was previously infected with the virus.

Adapted from https://www.cdc.gov/coronavirus/2019-ncov/covid-data/seroprevalance-surveys-tell-us.html

Did You Know?

COVID-19 is caused by one type of coronavirus, but there are many types of coronaviruses. For example, some common colds are caused by coronaviruses related to this new one. Antibody tests may not be able to tell the difference between those antibodies and ones made against this new coronavirus. Scientists also don’t know yet if having antibodies protects you from developing COVID-19 in the future.

Our Study

We worked with Quest Diagnostics to test stored blood samples given by participants. We started testing samples from March 2020. Then we worked backward until January 2, 2020. All together, we tested more than 24,000 samples, given by participants across the country.

Because this virus is new, antibody tests for it are still being fine-tuned. They may not be as accurate as tests for other conditions. A test could have false positive or false negative results. In a false positive, the test shows that someone was exposed to the virus when they weren’t. A false negative is when the test shows that someone was not exposed to the virus when they were.

The antibody tests we used are very new. They do not have full approval from the FDA. Instead, the FDA gave them Emergency Use Authorization. This authorization is used in public health emergencies like this pandemic. To make sure our results were as accurate as possible, we checked each sample with at least two different tests. When samples had a positive result on either of these tests, we checked them with two more tests.

What We Learned

This study taught us several important things. First, it showed that the virus that causes COVID-19 may have been in the U.S. earlier than we initially thought. It also may have spread to different parts of the country earlier than we thought.

Second, the study showed that antibody testing platforms may have different results, depending on the type of test. The coronavirus is shaped like a spiky ball. Some tests checked for antibodies that bind to the spikes coming out of the virus. Other tests checked for antibodies that bind inside the ball (the virus). The tests did not always get the same results.

The virus that causes COVID-19 may have been in the U.S. earlier than we initially thought.

Because we were able to compare different antibody tests, we learned more about how these tests perform. This information can help researchers decide how to plan antibody studies on COVID-19 in the future.

Where and When We Found Antibodies

All of Us tested 24,079 samples that participants had given between January 2 and March 18, 2020. Participants in this study came from all across the U.S., though we had more samples from some states than others. We found SARS-CoV-2 antibodies in 9 samples given in 5 states.

Who Had Antibodies

These graphics show data about the 9 people in our study who had antibodies. These data cannot tell us about everyone in the U.S., just the people who shared samples with us. All of Us works hard to include groups that have been left out of research in the past, like older adults and people of color. That’s why we have more positive results from those groups here.

These data also cannot tell us about how or why the virus spread. Many factors play a role in the spread of the virus and in how COVID-19 affects different groups and communities. Research has shown that no one group can spread the virus more than others.

The average age of people with antibodies was 58.2.

The number of cases All of Us found was nearly evenly split between people assigned male and female sex at birth.

People who had antibodies came from different racial and ethnic groups. These options are how people described themselves when they first signed up for the program.

Other options included "Asian," "Other," and "Prefer not to say." None of our participants with positive samples chose those categories.

How the Data Will Be Used

We have added the results to our database for approved researchers to use in more studies. No names, addresses, or other identifying information are included.

If your sample was tested as part of the study, we will contact you and let you know your result is available in your All of Us account. You can choose whether you want to see your test result.

Learn More

The results of this study have been published in the journal Clinical Infectious Diseases.

Read our press release.