Flu: Manufacturers adapt all three strains in vaccinations

Sick in bed (symbolic image): “Need better vaccination rate”

A peek every autumn: If you are 60 years old or older, you should get vaccinated against flu, recommends the Permanent Vaccination Commission – as well as pregnant women, people with certain pre-existing conditions or medical staff (you can read the complete list here).

In order to protect immunization as reliably as possible, vaccines composed of antigens of variants and strains circulating worldwide are regularly adapted. Unlike many other pathogens, flu viruses change rapidly.

In February, a prognosis is usually made for the virus variants prevailing in the following winter, according to the Paul-Ehrlich-Institut (PEI), which is responsible for vaccines in Germany. The decision is therefore based on recommendations from the World Health Organisation (WHO) and the Committee for Medicinal Products for Human Use of the European Medicines Agency.

For the upcoming flu season 2026/2027, all three strains included in the vaccines were adjusted. This was necessary because all three strains have changed significantly in recent years, says Leif-Erik Sander, director of the clinic for infectiology and intensive care at the Charité.

“I wouldn’t primarily conclude that we’re getting a much stronger flu season,” Sander said. With the still quite new influenza variant, A(H3N2) of the Subklade K, many people had already come into contact last year. The flu vaccine was also adapted to this variant. “Even in the southern hemisphere, where winter is now ending, there was not such a severe flu season,” says Sander.

However, the exact course of a flu season is difficult to predict, according to experts. Only so much is certain: “The flu wave always comes, you can basically set the clock after it,” says Sander. During the severe flu season 2017/2018, according to estimates, more than 25,000 people in Germany died of influenza, as flu in technical jargon is called.

How well a flu vaccine protects also depends on whether the adaptation of the vaccines is consistent with the actually circulating variants. Surely this can never be predicted.

But even if the vaccines do not fit optimally in a season, they can still often prevent many cases of illness. In addition, influenza is typically milder in vaccinated people.

In the 2024/25 season, according to the Robert Koch Institute (RKI), only 34.5 percent of people aged 60 and older were vaccinated against flu, significantly less than the EU average. The target is actually 75 percent.

“The adaptation of vaccines is important,” says Sander. “But above all, we need a better vaccination rate.” The optimal time is between mid-October and mid-December.

Sore throat, fever, matte? How to recognize the real flu – and what helps, read here.