Those with antibodies apparently have at least a few months of immunity.
People who test positive for antibodies after being sick with the virus that causes COVID-19 can be protected against re-infection for at least a few months, according to a new study.
Between January and August 2020, researchers from the National Institutes of Health analyzed three million antibody test results, also known as serology tests, from five commercial laboratories and two healthcare data analysis companies.
The researchers found that people with positive antibody tests 90 days after their initial antibody test were only about a tenth as likely as those who did not have antibodies. After 90 days, a positive test probably represents a new infection rather than viral shutdown of the original infection.
“The data from this study suggest that people with a positive result of a commercial antibody test have significant immunity to SARS-CoV-2, which means they have a lower risk of future infection,” said Dr. Lynne Penberthy, contributor. director of the National Cancer Institute’s research program, which led the study, said in a statement.
The results could help explain why reinfection seems relatively rare, and it could potentially lead to future decisions about reopening work and school, as well as the distribution of vaccines.
According to the researchers, additional research is needed to understand how long the protection lasts, who may have less protection and how differences between patients, such as underlying conditions, can affect the protection against reinfection.
The study was published Wednesday in JAMA Internal Medicine.
ABC News’s Stephanie Ebbs contributed to this report.
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