[www.nytimes.com]

How long might immunity to the coronavirus last? Years, maybe even decades, according to a new study — the most hopeful answer yet to a question that has shadowed plans for widespread vaccination.

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, happily, that these cells may persist in the body for a very, very long time to come.

The research, published online, has not been peer-reviewed nor published in a scientific journal.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 hospitalized 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.

And 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 consistent with encouraging evidence emerging from other labs. Researchers at the University of Washington, led by the immunologist Marion Pepper, had earlier shown that 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.

Akiko Iwasaki, an immunologist at Yale University, said she was not surprised that the body mounts a long-lasting response because “that’s what is supposed to happen.” Still, she was heartened by the research: “This is exciting news.”

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Saint Cloud, Minnesota, where the weather is wonderful even when it isn't.

I'm gonna believe the science I want to believe!

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Hurts like a bastid...

I get the vibe that this virus, while novel in the way it affects the body, is not inclined to break the rules of epidemiology in a major way. I think we'll be fine once we get one or more of these vaccines sorted out.

Something doesn't add up. We are seeing confirmed cases of folks with declining antibodies after about three months, and confirmed cases of reinfection after about that same amount of time. There is also a fair bit of evidence that this particular virus is not producing the same kind of long-term immune response as for SARS and MERS.

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Freya says, 'Hello from NOLA, baby!' (Laissez bon temps rouler!)

Antibody decline isn’t necessarily evidence for lack of immunity. There may be something in the physiology of reinfected persons to account for their state; this could be an undiscovered partial hole in their immune response—natural or acquired from the illness. It’s also within the realm of possibility that the relatively few cases of reinfection being reported are actually reactivations.

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Le poète doit vivre beaucoup, vivre dans tous les sens. - Verlaine

Quote
Marc Anthony
Antibody decline isn’t necessarily evidence for lack of immunity. There may be something in the physiology of reinfected persons to account for their state; this could be an undiscovered partial hole in their immune response—natural or acquired from the illness. It’s also within the realm of possibility that the relatively few cases of reinfection being reported are actually reactivations.

Pretty sure they've ruled out reactivations -- the person is getting reinfected with a different strain than they were originally infected with.

There is a lot of good data to show that this particular coronavirus is affecting the host's immune response, so as to blunt it... I've written about it here before, but look at ORF8.

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Freya says, 'Hello from NOLA, baby!' (Laissez bon temps rouler!)