Fever, severe fatigue, body aches and a never-ending cough… If you haven’t experienced these symptoms yourself in recent weeks, your loved ones have probably experienced them. Influenza activity is increasing throughout France. Public Health France explains this Wednesday that the flu is at an “exceptionally high level of intensity in hospitals”.
To cope with a large influx of patients, many health establishments had to trigger their “white plan” allowing them to take exceptional measures to deal with the epidemic. But how can we explain that so many people are affected by the flu this year?
Three viruses circulating at the same time
“The viruses circulating today are nothing exceptional,” immediately warns Bruno Lina, director of the national reference center for respiratory viruses at the Hospices Civiles de Lyon and member of Covars (Committee for monitoring and anticipation of health risks). “They are normal and do not carry virulence factors. » If there are more hospitalizations linked to serious forms, it is quite simply because more French people have been infected this year.
“What is particular today is the rate of circulation of these viruses,” continues the doctor. When we talk about the flu, we are talking about AH1N1, AH3N2 and B. The current epidemic includes these three viruses. “They co-circulated or co-circulate at the same time and therefore added to each other,” explains Bruno Lina. This generates groups of different patients who become infected one after the other. » Children, poorly immunized, are particularly likely to be contaminated by several viruses within a few weeks of each other.
Strong transmission during the holidays
If the diversity of these viruses and their rate of circulation can explain the duration of the epidemic, they do not alone justify its intensity. “It’s very difficult to know why there is a significant increase in the number of cases this year,” admits the professor. This is perhaps the combination of slightly less good immunity and the fact that intrinsically, it is likely that these viruses have a high transmission potential. »
Bruno Lina is, however, sure of one thing: “Viruses circulated abundantly during the end-of-year holiday period, which contributed to the increase in the number of cases. » If during the Covid-19 pandemic, the health authorities invited the French to respect barrier gestures, the instructions are much less present regarding the flu.
Less vaccination
Another particularity of the current epidemic: young people are sicker than in previous years. “Figures from Public Health France show that there are as many 16/65 year olds hospitalized in intensive care as there are over 65 year olds,” illustrates Bruno Lina. This is unusual but can be explained by the fact that AH1N1 circulated extensively. » This virus giving relatively severe forms particularly affects 25/50 year olds.
To learn more about the flu
Finally, last explanation: the level of vaccination, slightly lower than that of winter 2023/2024. “We probably have 1 to 2% fewer vaccinated people than last year,” says the doctor. “Seventeen million French people have received a voucher to be vaccinated but fewer than ten million have done so. This remains low. » To deal with the epidemic, Bruno Lina would see an interest in vaccinating people in contact with those at risk. “This is what we do for whooping cough with parents, for example. » Another solution, chosen by the United Kingdom: vaccinate children.
