Faced with viruses such as influenza, HIV or Covid-19, women often produce a better immune response than men. “Indeed, a large part of the immunity genes are located on the sex chromosome X, present in two copies in women, against only one in men.indicates a communicated from Inserm published on July 7, 2022.
Even though gene expression is largely repressed on the second X chromosome, between 15 and 23% of them remain active. And in particular the “Toll-7 type” cellular receptor, present in cells called “plasmacytoid dendritic cells”. In particular, it allows recognize the RNA of viruses and trigger an immune response through a special mechanism: type I interferons.
#COVID19 How to explain the more effective immune response of women against #SARS-CoV-2 ? A new study focuses on the production of an inflammatory molecule, IFN-α, to answer this question.
Read the press release on https://t.co/roInleigFapic.twitter.com/jfb93MiXMT
— Inserm (@Inserm) July 7, 2022
Researchers from the Toulouse Institute of Infectious Diseases sought to see if this “immune advantage” persisted in older women, by studying the effect of sex and age on the production of interferon alpha, a sub -category of type I interferons, on a cohort of 310 people aged 19 to 97. “Even though the number of plasmacytoid dendritic cells decreases with age and much more markedly in women, the secretion of IFN-α remained very much higher in the participants, even in the oldest of them. (over 80)”the statement said.
“However, the fact that the difference in IFN-α production between the sexes persists with age and remains greater in women well beyond menopause, cannot be explained by an effect of sex hormones, and suggests a key role of genetic factors linked to the X chromosome”concludes Jean-Charles Guéry, lead author.
More Covid deaths in men than in women
This new study confirms another, published by INED in March 2022.”In France, at any age, a man has a higher risk of dying within a year than a woman of the same age.“, note the INED report, published on March 24, 2022. A 70-year-old man was thus twice as likely to die as a woman of his age. The cause ? Men tend to drink or smoke more than women, and take more risks at work or in their leisure time. And the Covid-19 pandemic has only confirmed this gap. According to Public Health France, 57% of Covid patients who died in hospital were men.
If the excess male mortality due to Covid-19 is lower than that for all deaths before the age of 50, it increases dramatically from the age of 50. For example, a man aged 65 to 74 is 2.4 times more likely to die from Covid-19 than a woman. Normally, this ratio is only 2.1. “Excess male mortality with Covid-19 is higher than that observed for all causes of death in normal times“, analyzes France Meslé, co-author of the report.
This difference is explained by a greater risk for men of being contaminated, in particular because of their behavior – less respect for barrier gestures, less teleworking – or their comorbidities (high blood pressure, diabetes). From the age of 50, men are more likely to suffer from these pathologies, which make them more vulnerable to Covid-19. Conversely, women would be more attentive and pay more attention to their health.
France is in the European average
Within Europe, and particularly in Italy and Spain, excess male mortality is much higher than in France, but lower in England.
Nevertheless, the study notes that the risk of dying from the coronavirus has decreased in 2021, probably due to vaccination. Between the ages of 65 and 74, men were more likely to be vaccinated than women of the same age. “Surprisingly, men would have been more attentive than women in the case of vaccination against Covid-19“, ends the study.
Sources:
- Better understand the differences in immunity between women and men in the face of Covid-19, Inserm, July 7, 2022
- Covid-19 deadlier for men than for women, INED, March 2022
Read also:
- Covid-19: Age, standard of living, vaccination status… Who are the French people who have had a severe form of the disease?
- Covid-19: the virus would not be transmitted so easily by the hands
- 25% of severe forms of Covid-19 are explained by a genetic or immunological anomaly
