Covid-19 antibodies from a previous infection can significantly lower your risk of becoming infected again, according to a study published Wednesday in the journal JAMA Internal Medicine.
“The results of the study are actually a 10-fold reduction, but I would have reservations about that. In other words, it could be an overestimation of the reduction, it could be an underestimate of the reduction,” said Dr. . Douglas Lowy, chief assistant director of the National Cancer Institute, who was an author on the study.
“For me, the big message is there is a reduction,” he said. “The main tradeoff is that antibody positive after natural infection is associated with partial protection against re-infection.”
How they did the research: The researchers examined data from more than 3.2 million people in the United States who completed an antibody test between January and August last year.
Of the subjects tested, 11.6% tested positive for Covid-19 antibodies and 88.3% negative.
- 0.3% of those with antibodies later tested positive for Covid-19 infection, after 90 days.
- 3% of those without antibodies tested positive for reinfection in the same period.
But more research is needed to determine a causal relationship, how long protection against antibodies can last, and the risk of reinfection by a variant.