High fever, aching limbs and severe fatigue, these are some typical symptoms of influenza. Influenza is caused by viruses that can be transmitted from person to person via smear or droplet infection.

Unlike a simple cold (flu-like infection), influenza is a serious illness. Especially in people with weakened immune systems, pre-existing conditions or pregnant women, influenza can pose a high risk. Therefore, the Robert Koch Institute (RKI) recommends the annual flu vaccination for protection.

Since the pathogens mutate quickly, the vaccine is adapted each year to the currently circulating virus strains. The vaccines therefore only protect for the current season. In addition, efficacy diminishes the longer it has been since vaccination. "Therefore, all persons for whom seasonal flu vaccination is recommended should be vaccinated with the flu vaccine for the current season," informed the Federal Center for Health Education (BZgA).

But who should refresh their vaccination annually? The Standing Committee on Vaccination (STIKO) recommends the flu vaccination for:

• People 60 years and older
• Pregnant women
• Medical personnel and personnel in care facilities
• People who have an increased risk of infection due to contact with many people
• Persons with direct contact to poultry and wild birds

Vaccinating against influenza: when is the best time to vaccinate?

Anyone who is allergic to components of the vaccine, such as chicken protein, should not get vaccinated. However, a chicken protein-free vaccine is available. Children and adolescents with immune deficiency, severe asthma or salicylate therapy should not be administered the approved live vaccine by nasal spray, the BZgA pointed out. In any case, information should be obtained from a physician beforehand.

And when is the best time to have the preparation injected? Since the annual flu wave in Germany usually begins shortly after New Year's Day, the RKI recommends getting vaccinated from October to mid-December. After that, it takes about 10 to 14 days for the body to build up sufficient protection. Anyone who has missed the vaccination in these months can still catch up "even at the beginning or during the course of the flu wave," writes the BZgA.

Influenza: Why does influenza occur mainly in winter?

Why influenza occurs primarily in the winter months has not yet been conclusively scientifically researched. What is certain is that the viruses are more stable in cool temperatures and dry air. This makes them infectious for longer, according to the BZgA. In addition, viruses can penetrate the body more easily, as the dry air seems to dry out the mucous membranes in the nose and mouth.

Flu vaccination: These side effects can occur

Like any vaccination, flu shots can cause vaccine reactions and side effects. Most reactions to the vaccine disappear after one or two days. Severe side effects, on the other hand, are very rare. According to the BZgA, these side effects can occur:

• Redness or swelling at the injection site
• Chills
• Fatigue
• Nausea
• Muscle pain
• Stuffy or runny nose (with live vaccine via nasal spray)
• General feeling of illness with fever, fatigue, aching limbs, headache, and muscle pain

Influenza vaccine may be given along with the Corona vaccine. "Vaccination should be administered to different limbs in each case," the BZgA said. However, increased vaccine reactions are possible when doing so, it said. A study from the U.S. suggested that flu infection slows the spread of Corona viruses. However, researchers doubt it.

Image by LuAnn Hunt