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Sudden onset of illness with fever, muscle ache or headache are typical signs of flu

Photo: Tero Vesalainen / Getty Images

Back in December, the Robert Koch Institute (RKI) reported that the number of registered flu cases had risen significantly. Now, it says that, in retrospect, the flu wave began in the week starting December 16. At the National Reference Center for Influenza Viruses at the RKI, samples from patients with symptoms of an acute respiratory infection are regularly examined. To put it simply, a flu wave begins when influenza viruses are detected in every fifth sample.

For the weeks between 18 and 31 December, almost 9000 flu cases confirmed by laboratory analyses have so far been transmitted to the RKI, the report says. Due to the holidays, however, the figures for the last week of December can only be evaluated to a limited extent, as fewer tests are carried out during this time, among other things. In total, around 16,600 flu cases have been reported to the institute since October.

According to the current report, influenza A(H1N1)pdm09 viruses have recently been detected most frequently. School-age children and young adults are particularly affected. This subtype first appeared during the flu pandemic in 2009 – as a so-called swine flu. Since then, it has also been circulating seasonally in Germany, most recently significantly in the 2018/19 season.

In flu waves in which this pathogen dominated, it has so far been observed that very serious illnesses and deaths have also occurred in younger adults and children, especially when underlying diseases are present. "Overall, however, such severe courses are rare in young people."

In general, according to the RKI, older people in particular are at risk of becoming seriously ill with influenza or dying as a result of it. "The number of deaths can vary greatly during individual flu waves, from several hundred to over 25,000 in the 2017/18 season."

"Get vaccinated as soon as possible, if you haven't already done so"

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Flu is often noticeable by a sudden onset of illness with fever, muscle pain or headache, as the RKI informs. "Often, a dry dry cough is added a little later." A third of those infected have only mild symptoms, another third have no symptoms.

In 2022, the flu wave had already started in November and thus unusually early. In the years before Corona, it usually began in January and lasted three to four months, according to the RKI.

"All persons for whom the Stiko recommends the flu vaccination should be vaccinated as soon as possible, if this has not already been done," the current report says. This includes all people aged 60 and over, pregnant women, chronically ill people, residents of retirement and nursing homes and people with an increased occupational risk.

In the most recently evaluated week, Sars-CoV-2 (17 percent), RSV (15 percent) and rhinoviruses (11 percent) were detected in the samples sent in at the RKI in addition to influenza. RSV activity and Covid-19 activity remain high, according to the RKI. Since the end of June, a continuously increasing SARS-CoV-2 viral load has been observed in wastewater samples.

wbr/dpa