Scientists presenting the findings, from 100 non-hospitalised COVID-19 patients in Britain, said they were “reassuring” but did not mean people cannot in rare cases be infected twice with the disease. “While our findings cause us to be cautiously optimis

T-cell study adds to debate over duration of COVID-19 immunity A small but key UK study has found that "cellular immunity" to the pandemic SARS-CoV-2 virus is present after six months in people who had mild or asymptomatic COVID-19 - suggesting they might have some level of protection for at least that time. Kate Kelland U.S.

LONDON (Reuters) - A small but key UK study has found that “cellular immunity” to the pandemic SARS-CoV-2 virus is present after six months in people who had mild or asymptomatic COVID-19 - suggesting they might have some level of protection for at least that time.

Scientists presenting the findings, from 100 non-hospitalised COVID-19 patients in Britain, said they were “reassuring” but did not mean people cannot in rare cases be infected twice with the disease.

“While our findings cause us to be cautiously optimistic about the strength and length of immunity generated after SARS-CoV-2 infection, this is just one piece of the puzzle,” said Paul Moss, a professor of haematology at Britain’s Birmingham University who co-led the study.

“There is still a lot for us learn before we have a full understanding of how immunity to COVID-19 works.”

Experts not directly involved with the study said its findings were important and would add to a growing body of knowledge about potential protective immunity to COVID-19.

The study, which has not yet been peer-reviewed by other experts but was published online on bioRvix, analysed the blood of 100 patients six months after they had had either mild or asymptomatic COVID-19. It found that while some of the patients’ antibody levels had dropped, their T-cell response - another key part of the immune system - remained robust. ...