6 questions concerning the effectiveness of the vaccine this yr | EUROtoday
Get real time updates directly on you device, subscribe now.
HASWhen the month of January is already effectively underway, no area of France is proof against the epidemic. “We are seeing an intensification of the circulation of influenza,” notes Professor Bruno Lina, director of the National Reference Center for Respiratory Infection Viruses in Lyon, who’s analyzing the primary developments within the profile of those influenza viruses.
While Spanish and Italian hospitals are dealing with a large inflow of sufferers, specialists hope that this yr the composition of the vaccine would be the proper one. Understand every thing concerning the seasonal flu vaccine in 5 questions.
Is France more likely to undergo a state of affairs similar to that of Italy or Spain?
These two European nations are dealing with a number of respiratory epidemics on the similar time. Hospitals are saturated by the inflow of flu, Covid-19 and bronchiolitis sufferers. Spain is even calling for a return to masks in all healthcare institutions. France ought to profit from extra favorable circumstances. Indeed, the bronchiolitis epidemic has been slowing down for a number of weeks, maybe partly due to using a preventive remedy, Beyfortus. Same factor for Covid-19 with a reducing variety of circumstances, even when the circulation of the virus stays excessive in France.
Is seasonal flu attributable to a single virus?
No. “According to the first trends available in France, it is the A(H1N1) subtype which is the majority this year. It is responsible for 70% of infections. The other subtype identified is A(H3N2), but it is largely in the minority for the moment,” signifies Bruno Lina. Every yr, authorities monitor kind A and B influenza viruses as a result of they’re those that trigger winter epidemics. Three subtypes of the A virus flow into in people: A(H1N1), A(H3N2) and A(H2N2). Their baptismal title corresponds to the character of two proteins which compose them, hemagglutinin for H and Neuraminidas for N. Only A(H1N1) and A(H3N2) truly flow into in people presently, not the subtype B. This winter isn’t any exception.
How is the composition of the flu vaccine determined?
Influenza viruses evolve and mutate over time. Each winter, the strains in circulation should not precisely the identical as these of earlier seasons. They subsequently threat escaping our immune system. This is why it’s essential to adapt the composition of the vaccine earlier than embarking on its manufacture. Every yr, the formulation of influenza vaccines within the Northern Hemisphere is subsequently determined by WHO consultants between the months of February and March based mostly on the information out there on the winter viruses which completes and on these starting to flow into within the Southern Hemisphere. For the 2023-2024 season, the WHO decided on February 24, 2023. The vaccine used this yr is subsequently composed of an A(H1N1) virus, an A(H3N2) virus and two subtypes. of the B virus having circulated in 2022 or early 2023.READ ALSO Will bronchiolitis epidemics quickly develop into a foul reminiscence?
Is vaccine effectiveness good this yr?
“The first estimates place vaccine effectiveness between 60 and 65% against infections by the majority A(H1N1) subtype this year and which corresponds well to that contained in the vaccine. In people who are vaccinated and nevertheless infected with this subtype, we see that they benefit from a reduction in the intensity and duration of symptoms of around 60 to 65% as well,” estimates Bruno Lina. The effectiveness of this vaccine is subsequently relatively good, keep in mind that it’s most frequently between 60 and 70%, with a variation relying on age.
A(H3N2) developed in the course of the southern winter. It is subsequently true that vaccine effectiveness in opposition to it’s decrease.Bruno Lina, CHU Lyon
On the opposite hand, for the opposite subtype, the information is rather less optimistic. “A(H3N2) evolved during the southern winter. It is therefore true that vaccine effectiveness against it is lower. The number of cases is still low, since it is the minority subtype this year. We still lack data to estimate the level of real vaccine protection,” acknowledges the virologist. But it have to be emphasised that even when the effectiveness in opposition to an infection is decrease, vaccinated folks will nonetheless profit by having milder types of the illness. “Generally speaking, we know that the A(H3N2) subtypes are more difficult to target, because they evolve more quickly than the others and cause more serious forms,” underlines Brigitte Autran, president of the Committee. monitoring and anticipation of well being dangers (Covars), earlier than persevering with: “Among people hospitalized with a serious form of influenza, only 10% were vaccinated, the others were not. We can therefore deduce that the vaccine, even if it is not perfectly adapted, still provides greater protection against serious forms. »
Do flu vaccines often miss their target?
Remember that problems of adequacy between the strains contained in the vaccine and the circulating viruses occur on average every 3 to 5 years. But there is no absolute rule. Due to the vast majority of circulation of a subtype A (H3N2) virus, the first wave of influenza occurring after Covid-19 started early at the end of 2022. Its intensity increased. explained in part by a drop in collective immunity due to the pandemic, but also by the lower effectiveness of the vaccine.
Is it still useful to be vaccinated at this stage of the epidemic?
“Yes”, reply with out hesitation Brigitte Autran and Bruno Lina. The epidemic peak has not but been reached; it’s anticipated within the coming weeks, however the fashions should not but out there. You ought to subsequently not delay any longer, as a result of for cover in opposition to the flu to take impact, it takes roughly two weeks after the injection.
https://www.lepoint.fr/sante/grippe-6-questions-sur-l-efficacite-du-vaccin-cette-annee-10-01-2024-2549403_40.php#xtor=RSS-221