People who test positive for antibodies after being sick with the virus that causes COVID-19 may have protection against reinfection for at least a few months, according to a new study. Researchers from the NIH analyzed 3 million antibody test results … [and] found that people with positive antibody tests were only about one-tenth as likely as those who didn't have antibodies to test positive for the virus 90 days after their initial antibody test. After 90 days, a positive test likely represents a new infection rather than viral shedding from the original infection.