Researchers from the University of Oxford tested 12,000 frontline workers for COVID-19 antibodies. They evaluated them for 30 weeks and found that of the 11,052 study participants who did not have antibodies initially, 89 developed symptomatic COVID-19. None of the 1,246 workers who had antibodies got sick.

David Eyre, an infectious disease consultant at Oxford and one of the study authors, said on Twitter “it’s very unlikely, at least for 6 months,” that people can become reinfected with COVID-19.

According to Business Insider, the study authors wrote: “Prior SARS-CoV-2 infection that generated antibody response offered protection from reinfection for most people in the six months following infections.” The study was published in the preprint server MedRxiv.

This study mirrors the recent results of research from Iceland. Scientists measured the levels of SARS-CoV-2 antibodies in the blood of approximately 30,000 study participants, including 1,200 who tested positive for the virus and recovered. They found 91.1% of those who had recovered from COVID-19 had antibodies against the virus months after infection. Their results were published in The New England Journal of Medicine.

According to Nature, those protective antibodies actually rose during the two months after diagnosis and remained at high levels for an extended period of time.

“Our results indicate that antiviral antibodies against SARS-CoV-2 did not decline within 4 months of diagnosis,” wrote the authors.