Study Shows COVID-19 Antibody Drop In 94% Of People Within 60 Days - US Health Dept.

WASHINGTON (UrduPoint News / Sputnik - 26th November, 2020) Ninety-four percent of the 156 front-line health care workers who tested positive for the novel coronavirus had fewer antibodies 60 days later, included 28 percent who tested negative, the Centers for Disease Control and Prevention (CDC) said in a report on Wednesday.

"In this study of 156 frontline U.S. health care personnel who received positive SARS-CoV-2 [novel coronavirus] antibody test results in spring 2020 and returned for follow-up testing approximately 60 days later, 146 (93.6 percent) had a decline in antibody levels between baseline and follow-up, and 44 (28.2 percent) had complete seroreversion, i.e., a decline of antibody to levels below the threshold for positivity," the report said.

The results suggest that antibody tests - as opposed to tests for the disease itself - at a single time point is likely to underestimate the number of persons with previous coronavirus infections, and a negative antibody test result might not reliably exclude prior infection," the report said.

The report also suggests that an optimal window for donations of convalescent plasma to treat the novel coronavirus disease (COVID-19) occurs shortly after recovery because of a quick decline in antibody levels.

The duration of the immunity presents a key unknown with several vaccines expected to become available within months. However the report noted that memory B-cell and T-cell responses in the immune system might reduce the severity of illness with repeat exposure or infection, even in the absence of antibodies.