Immunity to the coronavirus may last years or even decades, according to a new study.
Eight months after infection, most people who have recovered still have enough immune cells to fend off the virus and prevent illness, the new data show.
A slow rate of decline in the short term suggests these cells may persist in the body for a very, very long time to come.
The research has not been peer-reviewed nor published in a scientific journal, but it is the most comprehensive and long-ranging study of immune memory to the coronavirus to date.
“That amount of memory would likely prevent the vast majority of people from getting hospitalised disease, severe disease, for many years,” said Shane Crotty, a virologist at the La Jolla Institute of Immunology who co-led the new study.
The findings are likely to come as a relief to experts worried that immunity to the virus might be short-lived, and that vaccines might have to be administered repeatedly to keep the pandemic under control.
The research squares with another recent finding: that survivors of Sars, caused by another coronavirus, still carry certain important immune cells 17 years after recovering.
The findings are also consistent with encouraging evidence emerging from other labs. Researchers at the University of Washington had earlier shown certain “memory” cells that were produced following infection with the coronavirus persist for at least three months in the body.
A study published last week also found that people who have recovered from Covid-19 have powerful and protective killer immune cells even when antibodies are not detectable.
These studies “are all by and large painting the same picture, which is that once you get past those first few critical weeks, the rest of the response looks pretty conventional,” said Deepta Bhattacharya, an immunologist at the University of Arizona. – New York Times