A UCLA study shows that in people with mild cases of COVID-19, antibodies against SARS-CoV-2 — the virus that causes the disease — drop sharply over the first three months after infection, decreasing by roughly half every 36 days.
If sustained at that rate, the antibodies would disappear within about a year.
The findings raise concerns about antibody-based “immunity passports,” the potential for herd immunity and the reliability of antibody tests in estimating past infections. In addition, the findings may have implications for the durability of antibody-based vaccines.
Previous reports have suggested that antibodies against the novel coronavirus are short-lived, but the rate at which they decrease had not been carefully defined. This was the first study to carefully estimate the rate at which the antibodies disappear. The researchers studied 20 women and 14 men who recovered from mild cases of COVID-19. Antibody tests were conducted at an average of 36 days and 82 days after the initial symptoms of infection.
— Enrique Rivero
“Rapid Decay of Anti–SARS-CoV-2 Antibodies in Persons with Mild Covid-19,” NEJM, July 21, 2020