A recent US study suggests that people who have already been infected with the coronavirus benefit from long-term immunity. These people would develop immune cells whose presence can be recorded over time. While the duration of this immunity cannot be precisely defined, these are very encouraging results.
While herd immunity is no longer an option to fight the pandemic, scientists continue to investigate the duration of patient immunization after infection with coronavirus SARS-CoV-2. A study published on the bioRxiv platform on November 16, 2020 is rather optimistic on the issue. Researchers from the University of California (USA) studied blood samples from 185 men and women aged 19 to 81.
Recovered, these people had mild symptoms when they were infected with the coronavirus. The researchers considered several elements involved in the immune system. Let's mention the B cells producing the antibodies as well as two types of T cells , whose mission is to destroy infected cells.
According to the results, the antibodies that patients develop remain in the body for between six and eight months before declining slightly. The same is true with T cells. On the other hand, the amount of B cells increases, but scientists do not know how to explain this phenomenon.
It is not known from this work how long immunity to the coronavirus lasts. On the other hand, they maintain the hope of a lasting immunity , which is a good sign for the evolution of the pandemic. In addition, remember that the first vaccines promised by Moderna, Pfizer or even Russia are not yet ready.
“We absolutely had to know if reinfection was going to be a problem. And so to see evidence that we have this type of persistent and robust response, at least on these time scales, is very encouraging […] Such a large amount of immunological memory would probably allow the majority of people not to be again hospitalized and badly affected by the disease for years" Shane Crotty, a co-author of the study, told the New York Times.
However, these works should be viewed with caution. Indeed, these have only been the subject of a pre-publication. In other words, the study has not yet been verified by peers.
