The effectiveness of the influenza vaccine is not good in the UK, Canada and the US. It should be better in France.
We already knew that the flu shot was not going to be very effective this year. Due to a mismatch between the A (H3N2) viruses circulating and those present in the vaccine. But in some countries, the situation seems to be worse than in France. These include the United Kingdom, Canada and the United States. Data was released last week in Eurosurveillance, the journal of the European Center for Disease Prevention and Control (ECDC).
None or very low
The figures show that in these countries “overall, the effectiveness of the influenza vaccine is either zero or very low”, sums up why Frenchman Daniel Lévy-Bruhl, from the Institute for Public Health Surveillance (InVS), who co -signed the editorial in the journal Eurosurveillance. But the epidemiologist prefers to stick to confidence intervals and not deliver raw data, which he says means nothing.
In France, equivalent estimates are not yet available, because the influenza epidemic was later than in the three countries studied. But the vaccine efficacy should be higher, believes Daniel Lévy-Bruhl. He therefore invites people at risk to continue to be vaccinated, the immunization campaign having been extended by one month, until the end of February.
In mid-January, Prof. Bruno Lina, head of the national influenza reference center (CNR) for the South of France, predicted why vaccine efficacy of around 30% to 40% this year.
Epidemic difference
But why could vaccine efficacy be higher in France, compared to the United Kingdom, Canada and the United States? “It’s just a question of the epidemic difference,” explains Daniel Lévy-Bruhl. According to the latest bulletin from the Sentinelles epidemiological surveillance network of Inserm, in France A (H3N2) represents 63% of circulating strains. In the United Kingdom, Canada and the United States this strain is much more present. However, it is this strain that mutated between the time the vaccine was made and the flu epidemic, thus reducing the effectiveness of the vaccine.
Peak reached in France?
In France, the peak of the flu epidemic could have been reached, according to the Sentinelles network. In four weeks of the epidemic, 1.49 million people would have consulted a general practitioner for influenza-like illness, including nearly 1.23 million for the flu.
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