Covid-19 antibodies from a previous infection could significantly lower your risk of becoming re-infected, according to a study published Wednesday in the journal JAMA Internal Medicine.
"The results from the study are basically a 10-fold reduction, but I would have caveats around that. In other words, it could be an overestimate of the reduction, it could be an underestimate of the reduction," said Dr. Douglas Lowy, principal deputy director of the National Cancer Institute, who was an author of the study.
"To me, the big message is -- there’s a reduction," he said. "The main takeaway is that being antibody positive after natural infection is associated with partial protection against a new infection."
How they did the study: The researchers examined data on more than 3.2 million people in the United States who had completed an antibody test last year between January and August.
Among those tested, 11.6% tested positive for Covid-19 antibodies and 88.3% tested negative.
- 0.3% of those with antibodies tested positive for Covid-19 infection later, beyond 90 days.
- 3% of those without antibodies tested positive for reinfection during the same time period.
But more research is needed to determine a causal relationship, how long protection from antibodies may last, and the risk of reinfection from a variant.