Antibodies to COVID-19 infection protect patients for six months

A new study suggests that people who have previously had COVID-19 are highly unlikely to contract the disease for at least six months after their first infection. The study was conducted as part of a collaboration between the University of Oxford and Oxford University Hospitals (OUH) National Health Service (NHS) Foundation Trust, both in the UK.

Researchers studied a 30-week period (April to November 2020) with 12,180 healthcare workers employed at OUH. The workers were tested for antibodies against SARS-CoV-2, the virus that causes COVID-19, as a way to detect who had been infected previously.

The hospital regularly tested staff for COVID-19, both when they became ill with symptoms, and as part of regular staff testing. The researchers then checked whether staff who had previously been infected had the same number of new COVID-19 infections as those who had not been previously infected.

During the study, the scientists found that 89 out of 11,052 staff members without antibodies developed a new infection with symptoms. None of the 1,246 staff members with antibodies developed a symptomatic infection. Staff with antibodies were less likely to test positive for COVID-19 without symptoms since 76 staff without antibodies tested positive compared to just three with antibodies. The three health workers with antibodies tested positive for the virus that causes COVID-19 were all well and did not develop symptoms of COVID-19 again.

Researchers suggest that most people are unlikely to get COVID-19 again if they’ve had it in the previous six months. Additionally, the team concluded that healthcare workers who did not have antibodies to COVID-19 were more likely to develop the infection.

One of the authors of the article, Professor David Eyre, said: “This ongoing study involving a large cohort of healthcare professionals has shown that COVID-19 infection offers protection against reinfection for most of the people for at least six months – we found no new symptomatic infections in any of the participants who tested positive for antibodies, while 89 of those who tested negative contracted the virus. This is really good news, because we can be sure that, at least in the short term, most people who get COVID-19 will no longer receive it. We know from a previous study that antibody levels decline over time, but this latest study shows that there is some immunity in those who have been We will continue to monitor this staff group closely to see how long the protection lasts and whether the previous infection affects the severity of the infection. one if people get infected again. “

The results were published in pre-press in medRxiv.