I’bronchiolitis outbreak is not over. It could even already be on the rise again, due to a post-school rebound effect. Even if it is not easy to make forecasts. “These last seasons have been very disturbed and it is complicated to announce when we will pass the peak”, commented this November 18 during a press briefing, Sophie Vaux, epidemiologist at Public Health France.
On November 13 on BFM TV, Olivier Véran, ex-Minister of Health, declared that the bronchiolitis epidemic was very strong, to the point of putting the h hospital and pediatric wards under strain, and that its virulence was explained by the fact that the children had been less immunized because of the anti-covid measures, in particular the wearing of the mask, for two years. “Why is it so intense? Precisely because for two years, we wore masks, and since it’s a respiratory virus, we had protection, so we had an epidemic that was very weak, we had fewer immunization of the little ones, and suddenly, as there is a collective relaxation, the virus circulates very strongly, it circulates earlier, and therefore there are many children who are sick.”
Immune debt: what is this theory based on?
Concretely the “immune debt” is caused by a loss of effectiveness of the body’s immunity to fight against infections, following a standby of the latter during the epidemic. In short, we would have “missed” opportunities to train our body to face external attacks, with the protection of the mask, and in fact, we would be more fragile today.
Release CheckNews published an article which emphasizes that the scientific community is divided on this principle of immune debt, and quotes Brigitte Autran, professor of immunology at the Faculty of Medicine of the Sorbonne and president of Covars, who says that “does not have a solid immunological basis“. In this same article, it is recalled that there has not been a total absence of a bronchiolitis epidemic for two years.
According to Santé Publique France, which also returned to this debate on November 18, immune debt has indeed been the source of several scientific publications. It would have had the effect of overall decline in children’s immunitybut also babies to be born less immunized by their mother during pregnancy, and consequently an increase in susceptibility to the RSV virus when it begins to circulate way stronger.
Co-circulation of respiratory viruses
Sopie Vaux, from Santé Publique France, also points out that immune debt is not the only hypothesis studied to explain the strong epidemic of bronchiolitis this fall. “The virus most often implicated in bronchiolitis, RSV, began circulating earlier this fall and coincided with the circulation of other respiratory virusesin particular the rhinovirus, which can also lead to cases of bronchiolitis, even if they are less severe. This co-circulation of respiratory viruses has been observed elsewhere in the Northern Hemisphere. “An earlier start of theflu epidemic am not excluded this year for the same reason”, has also noticed the scientist. Brittany is already in the “pre-epidemic” flu phase.
Santé Publique France recalls that preventive measures, including wearing a mask, are currently essential and more than ever necessary to protect the youngest from bronchiolitis.
It also publishes new recommendations in an information booklet for young parents, to consult here.
Sources:
- Is Olivier Véran right to link the virulence of the bronchiolitis epidemic to the avoidance of the virus, for two years, because of the wearing of a mask?, CheckNews Liberation, November 16, 2022.
- Public Health France press briefing, November 18, 2022.
