After being infected with Covid-19, the antibody level would be more stable and durable in women. They would thus be immunized longer against this disease than men.
- Anti-S antibodies are the most persistent, with 98% of participants having a detectable level within 3 to 6 months after infection.
- The level of anti-Covid-19 antibodies was on average lower in women in the first times after infection.
- The difference between men and women in the face of Covid-19 would be linked to hormonal, genetic and environmental mechanisms.
How long are you immune to Covid-19 after being infected? Immune responses are too variable from one individual to another to answer this question. Nevertheless, researchers from the National Institute of Health and Medical Research (Inserm) and the Pasteur Institute seem to have found a general trend: women are immunized longer than men. Their study has just been published in the journal The Journal of Infectious Diseases. Indeed, the rate of antibodies produced by women would be more stable and therefore more durable than that of men.
Anti-S antibodies decrease differently from one individual to another
To achieve their results, the scientists followed the evolution of 308 people for six months. All had contracted Covid-19 in a mild form. Regularly, the researchers dosed the antibodies – or immunoglobulins – of the patients. More specifically, these were those directed either against surface protein S (IgM and IgG), or against the nucleocapsid N (IgG) of the virus. “We found that anti-S antibodies were the most persistent, with 98% of participants having a detectable level within 3-6 months of infection, explains Samira Fafi-Kremer, who led this work in collaboration with Olivier Schwartz’s team from the Pasteur Institute. We also observed that this rate gradually decreases over time, but with a very different magnitude from one individual to another.“
Fewer antibodies in women immediately after infection
Regarding the differences between men and women, the scientists first noted that the level of anti-Covid-19 antibodies was on average lower in women in the early stages after being infected. But they then observed a less rapid and pronounced decline in them than in men, regardless of the age and weight of the patients. “We know, for example, that women generally have a more robust humoral and cellular response than men, whether in the face of other infectious diseases or in response to vaccination, insists Samira Fafi-Kremer. The deleterious side of this broader reactivity is that women are more often prone to autoimmune diseases.“The latter are manifested by a dysfunction of the immune system, which leads it to attack the normal constituents of the body. These are, for example, multiple sclerosis or type 1 diabetes.
Better consider the vaccine response according to gender
The difference between men and women in the face of Covid-19 would be linked to hormonal, genetic and environmental mechanisms. “A large part of the immunity genes are located on the X sex chromosome, which is present in two copies in women, against only one in men, develops Samira Fafi-Kremer. The expression of the genes present on this second chromosome is mainly repressed, but between 15 and 30% of these genes can escape this inactivation“. The researchers will continue beyond 6 months the follow-up of these patients in order to clarify their results and also better consider the differences in vaccine responses between men and women. “We will also be able to determine the incidence rate of reinfections, concludes Samira Fafi-Kremer. This will allow us to assess the extent to which the humoral response to a first infection makes it possible to be protected or not and, by extrapolation, to understand the protection offered by vaccination. Furthermore, we are measuring the maintenance of the lymphocyte response in the same group of patients at different follow-up times, to assess how memory immunity persists..”
Last December, a study published in the journal NatureCommunications already underlined the differences between the two sexes in the face of Covid-19. The researchers explained that men were three times more likely than women to enter intensive care and die from this disease.
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