By Francesco Guarasco
BRUSSELS (Reuters) – The flu has returned to Europe faster than expected this winter after almost disappearing last year, and has raised concerns about a long “rounding” with COVID-19 amid some doubts about the effectiveness of flu vaccines.
The COVID-19 pandemic, which has become commonplace in Europe, has led to the elimination of the flu last winter, the disappearance of a virus that kills around 650,000 people a year, according to EU data.
But that has changed because countries are taking less stringent measures to combat COVID-19 because the vaccine is widespread.
Influenza viruses have been circulating in Europe at a higher rate than expected since mid-December, the European Center for Disease Prevention and Control (ECDC) reported this month.
In December, cases of influenza in European intensive care units (ICUs) rose steadily to 43 in the last week of the year, according to data from the ECDC and the World Health Organization.
That’s far below pre-pandemic levels – more than 400 cases of the flu in the same phase in 2018 in 2018, for example.
But the rise is much higher than last year, when there was only one case of flu in an ICU throughout December, the data show.
The return of the virus could be the start of an unusual flu season, which could last until the summer, Pasi Penttinen, a leading ECDC flu expert, told Reuters.
“If we start lifting all measures, my main concern with the flu is that we have had almost no circulation in the European population for a long time, so maybe we will move away from the usual seasonal patterns,” he said.
He said the abolition of restrictive measures in the spring could extend the flu circulation beyond the normal end of the European season in May.
A “twindemia” could already put excessive pressure on excessive health systems, the ECDC said in its report.
In France, three regions – including the Paris region – are facing an influenza epidemic, according to data released by the French Ministry of Health last week. Others are in the pre-epidemic phase.
This season, France has so far reported 72 serious flu cases, with six deaths.
To make matters worse, the main strain of the flu that is circulating this year seems to be H3 of the A virus, which usually causes the most severe cases among the elderly.
Penttinen said it was too early to make a final assessment of the flu vaccine because a larger number of patients were needed for real-world tests. But laboratory tests show that the vaccines available this year “will not be optimal” against H3.
This is largely due to the fact that few or no viruses were circulating when the vaccine composition was decided last year, and it is more difficult for vaccinators to predict what strain will prevail in the next flu season.
Vaccines Europe, which represents the region’s leading vaccine manufacturers, admitted last year that it was difficult to select strains due to very low flu circulation, but that there was still not enough data to assess the effectiveness of shots this season.
Influenza vaccines are adapted every year to make them as effective as possible against the ever-changing flu virus. Their composition is decided six months before the start of the flu season, based on the circulation of viruses in the opposite hemisphere. This gives pharmacists time to develop and make plans.
Data on vaccination against influenza across Europe are not yet available. But French national data show that coverage is not as broad as authorities expected.
Local authorities extended the vaccination period by a month until the end of February to strengthen the vaccines. According to data released last week, 12 million people have been vaccinated so far, about 45% of the target population.
“There is still a long way to go to limit the impact of the flu epidemic,” the health ministry said in a statement on Jan. 11. This year’s goal is to vaccinate 75% of people at risk.
Vaccines Europe said the industry has issued a number of flu vaccines, despite tensions at pandemic production facilities.