Vaccination against the influenza virus

What is the flu?

An increasing number of people are getting the flu, especially during the cold season. That's why the flu is also called seasonal flu. It is an acute infectious respiratory disease caused by certain influenza viruses. The flu usually starts suddenly with a high fever, dry cough, sore throat, muscle aches, and headache. The symptoms typically affect not only the respiratory tract but the whole body. Those affected suddenly feel unwell.

Other illnesses, such as the common cold, can cause similar symptoms. That's why the common cold is also called a "flu-like infection." However, the common cold is caused by different viruses than the flu.

Leading countries in the field of medicine agree that the best protection against the flu is vaccination. People who experience treatment in Switzerland complications after the flu are mostly those who are not vaccinated. Flu vaccines are dead vaccines that contain only inactive parts of the virus. The human immune system responds to this with an immune response, which includes the production of antibodies. Some people may have a noticeable reaction to the vaccine, not only locally near the injection site but also systemically, in the form of discomfort, headaches, body aches, nausea, or fever. However, this rarely happens with the flu vaccine and lasts only a day or two.

What are the symptoms of the flu?

Everyone is familiar with common cold symptoms like a runny nose, cough, and a scratchy throat. The flu can have very similar symptoms, but they are usually more pronounced.

Typical flu symptoms include:

• Sudden onset of high fever
• Dry, hacking cough or sore throat
• Muscle pain and body aches
• Severe headache

General weakness, sweating, and nasal congestion

Especially in children, the flu can lead to gastrointestinal problems such as nausea, vomiting, and diarrhea.

The clinical picture of the flu is quite varied. Not all infected individuals have typical flu symptoms. About one-third of those infected actually have a fever and typical symptoms, another third have only mild cold-like symptoms without a fever, and the last third remain asymptomatic.

Especially in older people or those with weakened immune systems, high fever and pronounced signs of illness are often absent. However, in older people, symptoms such as confusion and disorientation can also occur.

Influenza Vaccination

Real viral influenza (the flu) is not a simple cold but a serious illness. In particular, it is advisable to vaccinate those with chronic illnesses, individuals over 60 years of age, and pregnant women because these groups are at an increased risk of developing severe complications. The vaccination recommendation also applies equally to healthcare personnel since a large number of close contacts with patients usually increases the risk of infection. There is also a risk that they will transmit the flu virus to their patients, possibly even without realizing it.

Flu vaccination should be done annually, preferably from October to mid-December. After vaccination, it takes 10 to 14 days for the body to establish adequate protection against the infection. Later vaccination at the beginning of the year is usually still beneficial, especially if the flu epidemic has not yet begun or has just started.

EFFICACY AND IMPACT

Protection against the flu is achieved within 

two weeks after vaccination

should be practiced every year in the fall to protect against the upcoming winter epidemic. Only one injection is required.

The vaccine composition is updated annually in line with the recommendations of the World Health Organization (WHO) and takes into account the viruses most likely to circulate during the seasonal epidemic. The flu is unpredictable, and the vaccine's effectiveness varies from year to year. The vaccine is more effective when the types of flu virus selected for its development are close to the strains that are actually circulating during the seasonal epidemic.

Many vaccinated individuals believe they have had the flu despite getting the vaccine. This can be due to two reasons:

• It is indeed the flu, and the person did not respond to the vaccine because its effectiveness is not 100%.
• It is not actual flu but another virus (viral infection) with symptoms similar to the flu.

In any case, the vaccine cannot cause the flu because it contains only an inactivated fraction of the virus.