Positive side effect

Flu strain eradicated by corona measures

(Bild: P. Huber)

Some people may have already wondered: From this season, a triple vaccine is recommended instead of the previous quadruple vaccine. It offers protection against only three instead of four influenza virus strains. This is not a cost-saving measure, but is due to a side effect of the coronavirus measures.

"We have completely eradicated one flu strain," says Carsten Watzl from TU Dortmund University. "This shows very impressively how effective the measures were."

Triple vaccine again this year
Until 2018, a triple vaccine was standard. Since the 2018/2019 flu season, a quadruple vaccine has been recommended by the Standing Committee on Vaccination (Stiko) in Germany. For the start of the season, the triple vaccine has now been recommended again as standard flu protection - without antigens against the flu strain B Yamagata.

Suddenly no more evidence
Experts had already established in 2020 that this group of influenza viruses was no longer circulating. Immunologist Watzl says that B Yamagata has also not been detected in the years since. According to an article in the specialist journal "Lancet", B Yamagata is the only respiratory disease-causing virus that was brought to extinction in the course of the corona pandemic - although caution is still required: not every corner of the world is well monitored, it is possible that B Yamagata has survived somewhere.

In September 2023, the World Health Organization (WHO) came to the conclusion that the B Yamagata component is no longer needed for vaccination protection. The so-called trivalent vaccine will now only contain antigens from one influenza B strain (B Victoria) and two influenza A strains. Different variants of these subtypes circulate around the world, with varying degrees of severity in each flu season.

Weighing up for the upcoming season
Every year in February, the WHO considers how the vaccines for the coming season should be designed to provide the best possible protection. As it is difficult to predict the dominant strains in each case, for years the focus has been on quadruple vaccination protection against two A and two B strains. This increases the likelihood that the vaccine will be effective against the strains that are actually circulating.

Influenza is a highly contagious infectious disease. Its course is much more severe than that of "flu-like infections", as colds caused by other pathogens are often called. In most cases, fatigue, high fever and a dry cough occur suddenly. In Germany, tens of thousands of people fall ill with influenza during the winter months.

Several deaths every year
Influenza viruses reduce the immune system and make the body susceptible to life-threatening complications: according to the RKI, influenza-related deaths are usually caused by bacterial pneumonia after the influenza viruses have damaged the lungs. The number of deaths varies greatly from season to season - from several hundred to over 25,000, as in the 2017/18 season.

The Stiko recommends an annual vaccination in the fall for people aged 60 and over or if there is an increased health risk, for example due to an underlying illness. Although vaccination does not offer one hundred percent protection against the disease, it does ensure a milder course. Antibiotics, on the other hand, are ineffective against influenza, as with all diseases caused by viruses. However, they are used if complications caused by bacteria also occur.