NIH: Antibodies protect against COVID-19 reinfection

After having COVID-19, most people develop antibodies to help fight it off and are less likely to get the virus again according to a new study.

A study reported by the National Institutes of Health states that researchers looked at more than 3 million people who had an antibody test for SARS-CoV-2 which is the virus that causes COVID-19.

They found that about 11% of people had the antibodies. More than 88% had a negative test. And less than 1% of tests were inconclusive.

The study then looked at who came down with COVID-19 after the antibodies test. They analyzed up to 30 days, 31–60 days, 61–90 days, and more than 90 days after.

“About 3% to 4% of people with negative antibody tests got COVID-19 in each time period. But those who had antibodies were less likely to have COVID-19 as time went on. Only 0.3% of the people with antibodies had a positive COVID-19 test more than 90 days after. Those without antibodies were 10 times more likely to get the disease.”

The findings suggest that people who have a positive result from an antibody test may be at lower risk for future infection with SARS-CoV-2, but does not mean people are never infected twice.

NIH’s Dr. Lynn Penberthy, who led the research team, states that more work still needs to be done. “We are nevertheless encouraged by this early finding,” she says.