Most people who've contracted COVID-19 will be immune from the virus for at least five months and have a low risk of catching it again, according to new research. Public Health England, which analyzed the results of coronavirus and antibody tests taken by nearly 21,000 healthcare workers from June to November, found past infection resulted in an 83% lower risk of contracting COVID-19 compared with those who had no coronavirus antibodies, suggesting they were never infected. Two "probable" infections and 42 "possible" infections appeared among 6,614 workers with antibodies during the study period, while 318 likely cases appeared among remaining workers without antibodies. If reinfected, "it is highly unlikely you will develop severe infections," study author Susan Hopkins tells the BBC. However, there is still a risk of passing the virus to others.
In some cases, healthcare workers were reinfected with high levels of the virus but experienced no symptoms. Researchers will monitor these healthcare workers for another year to get a fuller picture of naturally acquired immunity. But for now, it "appears to last at least for 5 months from first becoming sick," according to the study—which has not been peer-reviewed, per CNN—meaning "people who contracted the disease in the first wave may now be vulnerable to catching it again." That's why "now more than ever, it is vital we all stay at home to protect our health service and save lives," Hopkins says. Indeed, the study shows "the vast majority of the population will either need to have natural immunity or have been immunized for us to fully lift restrictions on our lives," Simon Clarke, an associate professor of cellular microbiology at Reading University, tells Reuters. (Read more coronavirus stories.)