Bronchiolitis. epidemic difficult to analyze

An epidemic of bronchiolitis, which mainly affects infants, has reached its highest level of hospitalizations in more than ten years, France’s Public Health Service (SPF), which is responsible for controlling it, announced this week. In the first week of November, half of emergency room visits by children under 2 were due to illness, and one-third of children who came for that reason were hospitalized during that time. On Wednesday, the Minister of Health launched the national plan for exceptional health situations (Orsan).

How to explain this wave that is flooding many hospital pediatric services already weakened by the hospital crisis? “This year, the bronchiolitis was initially more severepay attention to P^r: Isabelle Clauden, Head of Pediatrics and Pediatric Emergency Department at Toulouse University Hospital. Currently, we have as many children in the intensive care unit as at the usual peak of the epidemic, although this peak is not expected in our region until early December.

Maybe we should see the traffic impact “accompanying and unusual” several viruses that cause bronchiolitis, the SPF reports. RSV (respiratory syncytial virus), the main cause of bronchiolitis, is circulating earlier this year. This advance in the calendar brings it in line with rhinoviruses (a classic this season) and metapneumoviruses, all of which can cause the same symptoms; The baby may have problems feeding and breathing. Co-infections (simultaneous infections with two viruses) that contribute to this context are known to cause more severe cases.

Another hypothesis has been put forward “immune debt”, a concept developed by scientists during the Covid pandemic to explain the virulence of some seasonal epidemics. Low virus circulation due to barrier measures (blockades, masks, ventilation, etc.) would reduce the collective protection offered by regular exposure to these microbes. Mahmoud Zureik, a professor of public health at the University of Saint-Quentin-en-Yvelines in Versailles, cautions against jumping to conclusions, however. “It’s an attractive concept, but one that hasn’t been scientifically proven yet. We need to let research continue on this topic. The risk is that people, the general public or decision-makers, conclude that protecting themselves is useless because sooner or later they will have to be infected to somehow pay their debt. Assuming the hypothesis is true, we can accumulate debt by avoiding ever contracting the virus thanks to obstructive gestures, and thus never paying off said debt.

Pressures on hospitals

What about the evolution of the epidemic? “We are looking at the replacement of the rhinoviruses responsible for the first cases of bronchiolitis that are developing, says Bruno Lina, Director of the Influenza Virus Reference Center in the Southern Region. This is not so good news. RSV causes more severe bronchiolitis in young children.

Therefore, the pressure on hospitals should not be eased immediately. However, it is difficult to make predictions, the virologist emphasizes. “The SARS-CoV-2 outbreak has disrupted the known dynamics of other respiratory viruses.” Before the Covid-19 pandemic, epidemics of bronchiolitis were very regular, peaking at around 50.^e week of the year. But “Now it’s too complicated to model the evolution of the epidemic, it’s very worrying.”, confirms Isabelle Claude. Therefore, it is difficult to predict emergency room visit volumes and required staffing. Its foundation has led to an annual recruitment drive through August to bolster teams for winter epidemics. “But other hospitals are struggling, especially in areas where doctor and nurse positions are less attractive than they used to be.”