New York Times: Coronavirus immunity after infection can last a few years or longer, new study shows | News, foreign news | Freedom

Eight months after being infected with the novel coronavirus, most cured people still have enough immune cells to prevent infection and prevent disease, according to data from the “Immune Memory in SARS-CoV-2” study, conducted by researchers from the La Jolla Institute of Immunology, California.

According to new data, a slow short-term rate of decline suggests, fortunately, that these immune cells can persist in the body for a very long time, years or even decades.

The research has not yet been published in a scientific journal, but it is the longest and most comprehensive study of coronavirus immune memory to date.

The study looked at blood samples from 185 men and women between the ages of 19 and 81 who recovered from COVID-19. Most had mild symptoms that did not require hospitalization. Most provided only one blood sample, but 38 provided several samples over several months.

The team looked at four components of the immune system: antibodies, B cells that produce more antibodies when needed, and two types of T cells that kill other infected cells. The idea was to build a picture of the immune response over time.

The researchers found that the antibodies were durable, with modest reductions six to eight months after infection, although there was a 200-fold difference in levels between participants.

A small number of infected people in the new study did not have long-term immunity after recovery, possibly due to differences in the amounts of coronavirus they were exposed to. But vaccines can overcome this individual variability, said Jennifer Gommerman, an immunologist at the University of Toronto.

“We have to be very careful about whether or not reinfection is going to be a problem,” said Dr. Shaman, who led a study that suggested that immunity could wane quickly and that reinfection could happen within a year. .

“It is therefore very encouraging to see the evidence that we have such a persistent and robust response, at least in these time scales. So far, at least, coronavirus reinfections appear to be rare,” Shaman said.

Study participants have so far produced these cells in significant quantities. “There is no sign of the memory cells suddenly dropping, which would be a little unusual. There is usually a slow decline over the years,” said Dr. Iwasaki.

“I don’t think it’s an unreasonable prediction to believe these components of immune memory will last for years,” says Dr. Bhattacharya.

The new findings could likely come as a relief to experts worried that immunity to the virus could be short-lived and that vaccines would need to be given repeatedly to keep the pandemic in check.

University of Washington researchers, led by immunologist Marion Pepper, also showed that some “memory” cells produced as a result of coronavirus infection persist in the body for at least three months.

Akale Iwasaki, an immunologist at Yale University, said she was not surprised that the body has a long-term response because “this should happen.”

In recent months, reports of a drop in antibody levels have raised concerns that coronavirus immunity may disappear within months, leaving people vulnerable to the virus again. On the other hand, many immunologists have noted that it is natural for antibody levels to drop. Furthermore, antibodies are only one arm of the immune system.

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