“Using real-world data from more than 3 million people, NCI researchers and our collaborators have found that people who have had evidence of a prior infection with SARS-CoV-2, the virus that causes COVID-19, appear to have some degree of protection against being reinfected with the virus.
Exit DisclaimThis finding may explain why reinfection appears to be relatively rare and helps to confirm what many have hoped would be the case since the emergence of the virus.
Some may wonder why NCI is conducting research on COVID-19. Earlier this year, Congress appropriated $306 million to NCI in emergency funding to study the immune response to SARS-CoV-2. This project is one of many in this area that NCI has taken on at the request of Congress.
The NCI research team, which I was a part of, was led by Lynne Penberthy, M.D., M.P.H., associate director of NCI’s Surveillance Research Program. Working with two health care data analytics companies (HealthVerity and Aetion) and commercial labs (Quest and LabCorp), we obtained serology (antibody) testing results for more than 3 million people, representing more than 50% of the commercial SARS-CoV-2 antibody tests conducted in the United States. Nearly 12% of these tests were antibody positive; most of the remaining tests were negative (less than 1% were inconclusive).
The research team then looked at what fraction of individuals in each group went on to later develop a positive result on a nucleic acid (PCR) test for SARS-CoV-2, which may indicate a new infection. We found that, 90 or more days after the initial antibody test, people who had been antibody-negative had evidence of infection (a positive PCR test) at about 10 times the rate of people who had been antibody-positive.
This protective effect is strong and comparable to the protection afforded by effective SARS-CoV-2 vaccines, although developing protection from vaccination is much safer than from natural infection. This finding suggests that people who have a positive antibody test result using widely available assays have substantial immunity to SARS-CoV-2 and are at lower risk for future infection…”