Wednesday, May 29, 2024

COVID-19: Immunity of infected people can last for several years

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In some cases, the presence of antibodies can be detected in infected people up to thirteen months after they contract Covid-19, he asserts. the world Not to mention there are “memory” cells that, if infected again, can quickly transform into cells that secrete antibodies.

(Illustrative image) (AFP / DENIS CHARLET)

This is somewhat reassuring news. At a time when vaccination campaigns against the Covid virus are in full swing, especially in Western countries, let’s take a glimpse into the light at the end of the tunnel, a series of recent studies have revealed. The durability of the immunity of the former patients Even more after the vaccine is injected the world.

While the first results confirmed a strong decline after a few months, a study published earlier in May (that is, before peer review) and conducted on health workers at the University Hospital of Strasbourg already shows the presence of antibodies that identify and neutralize the virus. It persists in the body for up to thirteen months after infection with the Covid-19 virus. “Antibodies are produced in number for as long as the pathogen is present in the body, before rapidly decreasing within seven months of infection, to finally stabilize at a lower but steady level” , specified the world . “This is very good news,” Samira Favi Kramer, Director of the Strasbourg Institute of Virology, rejoices at the study’s origin.

Many studies also show the presence of infected people in the body Lymphocytes are called “memory” Which, if re-infected, can quickly turn into antibody-secreting cells. Their number will remain relatively stable for up to twelve months after infection, according to the study by Michelle Nussensweg of New York’s Rockefeller University, previously published on May 9. “All the time, cells go through mutations that improve the quality of their immune response and their ability to produce neutralizing antibodies,” the daily explains.

These memory cells are also able to adapt to changes , outlines Jean-Daniel Lillefer, Head of Clinical Immunology and Infectious Diseases at Henri Mondor Hospital, in Creteil (Val-de-Marne). “In general, the response developed after infection appears to be of high quality. All these data are fairly reassuring regarding immunity to SARS-CoV-2,” emphasizes the latter.

Covid-19 vaccine + = ‘immune response leaders’

But not everyone has the same immunity, and Even infected people should be vaccinated , the American researcher Ali H. insists. Al Yabidi, who published a study in دراسة nature May 24. This is confirmed by the work of Michael Nussensweg, which highlights this Vaccination increases B cells and antibodies , and “that recovering people who receive the (currently) available messenger RNA vaccines will produce antibodies and memory B cells that should protect against variants.” Injecting the vaccine will increase the body’s ability to neutralize by about fifty times , specified the world.

“clearly, The best preparation is for people who have had a mild form of Covid-19, followed by an injection of a vaccine : These are the leaders of the immune response to SARS-CoV-2,” comments Guy Goruchov, head of the Center for Immunology and Infectious Diseases at Pitié-Salpêtrière Hospital in Paris. it is obvious that Vaccination boosts antibodies and memory, so we can hope for protection for several years.” Samira Favi Kramer insisted.

Then what about vaccinating people who have never been infected? “The immunity of people who have just been vaccinated will not be as strong as that of people who are already infected.” Because the infection secretes antibodies against several proteins of the virus,” explains Samira Favi Kramer.

A third dose of the vaccine?

For Michel Nussenzweig’s team, the solution could lie in a third dose. “An additional boost in time with available vaccines could cover most variables of concern.” Explains his team.

For Jean-Daniel Lelliver, “there is a real link to the third dose” because “as the vaccine increases, we have antibodies against almost all variants and those antibodies decline for much longer.” A device not yet planned In France, the health authorities consider the vaccination cycle to be completed after two doses of vaccines (Pfizer, AstraZeneca and Modern, and only one for Janssen) or one dose after infection. However, the Ministry of Health ensures that all options are “pre-emptive”.

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