Covid: why some patients have serious forms even when vaccinated, the first elements of the answer

A committee of French and American researchers has discovered a lead, which could explain why some people develop serious forms of Covid, despite vaccination.

The anti-Covid vaccine prevents the development of serious forms and yet. Some patients have severe forms, despite the protection that the vaccine is supposed to confer. A privileged argument for opponents of vaccination and a real question for researchers.

But a study now provides an answer to these situations, which are still very rare. According to the study, conducted by researchers from Inserm, Paris Cité University and Rockefeller University in New York, an immunological deficiency would explain “nearly a quarter of the very rare severe forms observed in the vaccinated”.

The role of type 1 interferons

In a publication, Inserm explains “that approximately 20% of cases of serious pneumonia following infection with SARS-CoV-2 caused by genetic abnormalities (5% of cases) and immunological (14% of cases) which weaken the immune response carried by type I interferons.

Simply put, these type I interferons are proteins produced by body cells after viral infection to prevent “replication of the virus in infected cells”.

To try to better understand this weakening of the immune response, the study focused on “48 patients aged 20 to 80 who had a severe to critical form following an infection with the delta variantdespite a complete vaccination schedule by mRNA vaccine”.

Vaccine protection despite everything

After verifying that the vaccination had worked well, the researchers measured the “presence of type 1 anti-interferon autoantibodies”. The results speak for themselves: of the 42 remaining patients (6 had had a defective vaccine response), 24% had antibodies that could neutralize type 1 interferons.

The study also recalls that despite the serious form developed by these patients, no death is deplored, undoubtedly an effect of vaccination, since in the non-vaccinated, 20% of people who die from Covid “present self- anti-interferon type 1 antibodies”.

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