New study: COVID-19 immunity remains strong 8 months after contracting the disease

A new study reveals that people who have recovered from COVID-19 are likely to have immunity to SARS-CoV-2 for up to 8 months or more, induced by long-lasting immune memory of the body.

The study, which was conducted by researchers at La Jolla Institute at La Jolla, California, observed all the four branches of the “adaptive” immune system, which is known to guard against specific infections, in people who have recovered from COVID-19. 

The study found that between 5 and 8 months after the beginning of their symptoms, about 95% of these individuals’ adaptive immune systems showed to have retained a memory for the infection, in at least three of its above-said branches. This immune memory, the study said, is what enables the immune system to remain active against the virus. 

“Our data suggests that the immune response is there – and it stays,” says Prof. Alessandro Sette, who is one of the lead authors of the study. Prof. Shane Crotty, another lead author of the study, said “As far as we know, this is the largest study ever for an acute infection that has measured all four components of immune memory.”

Prof. Sette and his colleagues examined 254 blood samples from 188 individuals who recovered from COVID-19, from which, 43 samples were taken at least 6 months after the infection. The team measured the level of antibodies, memory B cells, and two types of T cells, which were all targeted at the virus. 

They found that the levels of antibodies targeted at the spike protein continued to remain fairly stable for at least 6 months. There’s also reasonable speculation that the production of antibodies by these cells is likely to accelerate after a second consecutive infection. 

Although researchers believe that it’s a good sign that antibodies, memory B cells and T cells, remain active in a person’s blood for more than 8 months, they did find a large difference in the magnitude of immune memory in different individuals. This indicates that not all people who have recovered from COVID-19 will have long-lasting immunity against the virus. The authors also mentioned that further studies should include more longitudinal data for a more precise understanding of the properties of antibody defenses against the virus.





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