Fall is here and with it comes flu season. Because of the corona measures, it has hardly been noticeable in the last two years. But the flu could return this winter – and possibly earlier and more severely than usual.

Nobody can predict exactly how the flu viruses will spread this year. And nobody knows how the numbers of Sars-CoV-2 infected people will develop in the next few months. But one thing is certain: If it gets colder outside, then the number of cases will also increase. The reason is the cold air, which can absorb less moisture than warm air. In addition, because of the cold, people stay longer in rooms that are heated. However, the cold air that comes in from outside brings hardly any moisture with it, so that it can become very dry, especially indoors.

In this drought, aerosols containing the viruses stay in the air longer. At the same time, the mucous membranes of the airways, which are considered the entry point for flu and corona viruses, but also for a number of bacteria, become drier than usual. Pathogens can adhere more easily to dry mucous membranes and ultimately penetrate the cells. This is the beginning of an infection. The corona measures, such as wearing masks or the distance regulations, have made it difficult for pathogens in the past two winters. But that could change with the abolition of the measures this year.

In order to make a forecast for the flu season 22/23 in this country, the experts also look to the other side of the world. In Australia, the flu season is already over. The official figures show that there was an influenza epidemic there in 2022, which peaked unusually early, i.e. at the end of May to the beginning of July instead of the usual July and August. As of July 31, the National Notifiable Diseases Sureveillance System also confirmed 212,573 cases, the highest number of flu cases in five years. More than 50 percent of influenza cases affected children under the age of 16. In their case, however, the disease was usually less severe.

But overall it is a largely normal flu epidemic in Australia. Professor Carsten Watzl also sees it this way: “Ultimately it was a flu wave, as in previous years, so nothing special. At the moment I would also assume that we will now see cases of flu again. One can only hope that it won’t becomes too strong,” said the Secretary General of the German Society for Immunology in an SWR interview.

“How well Germany will get through the 2022/2023 influenza season depends primarily on the vaccination rates. And unfortunately these are still too low in the risk groups,” said Sabine Wicker, head of the company medical service at the University Hospital in Frankfurt, according to the dpa. Wicker is a member of the Standing Committee on Vaccination (STIKO) and the STIKO Influenza Working Group. The rate for pregnant women was particularly low at 23 percent in the 2020/21 season. Wicker emphasized that despite the unpredictability of the severity of the wave this year, she considers influenza vaccination to be particularly important.

At an event in mid-September this year, Thomas Dittrich, chairman of the German Association of Pharmacists, also appealed to the population to be vaccinated: “There are good reasons to be vaccinated in the fall. First of all, the pandemic is not over yet, and we should “We are doing everything we can to avoid additional burdens from other infectious diseases. And secondly, the risk of contracting flu is likely to be greater for many this fall because the immune system is not well prepared for the pathogen after two years of low flu numbers.”

The flu vaccinations have been delivered since the end of September. With 22 million vaccine doses, the Paul Ehrlich Institute released an unusually early, unusually large number of vaccine doses. In total, it should be 28 million for this season. The first people in Germany have already received their flu shots, some of them in pharmacies. Because they are allowed to carry out the immunization for the first time this season with the appropriate equipment and after medical training. This model project aims to make it even easier for citizens with statutory health insurance to be vaccinated against influenza.