How often does flu occur?
Flu, or influenza, is a highly contagious infectious disease of the upper respiratory tract. It is caused by influenza viruses and is transmitted by droplet or smear infection. In Switzerland, epidemics occur between November and April every year, affecting 5 to 10 percent of adults and 20 to 30 percent of children. Estimates suggest that, in one season, several thousand people are hospitalised for flu or its consequences; several hundred die from it.
How to recognise flu
In contrast to a cold, flu is characterised by severe symptoms that appear suddenly. These include fever above 38 degrees, chills, sore throat, pain when swallowing, headaches, muscle and joint pain, and sometimes breathing difficulties. In children, diarrhoea and stomach pain can be the main symptoms. Older people sometimes experience flu without a fever.
When can flu become dangerous?
Complications can occur due to the virus itself or due to secondary bacterial infections. Most common are respiratory problems, middle ear infections and pneumonia. Certain patients are particularly at risk (see next question).
Which persons are advised to have a flu vaccination?
Persons aged 65 and over
Pregnant women and women who have given birth within the last 4 weeks
Premature babies from 6 months during the first two flu seasons
Persons (from the age of 6 months) with chronic diseases of the heart or lungs, metabolic disorders, an immune deficiency or a body mass index over 40
According to the recommendations of the Federal Office of Public Health (FOPH), vaccinations are also recommended to those who regularly come into contact with the above-mentioned risk groups in their professional or private lives, i.e. health care professionals or family, for example. This reduces the risk of the infection being passed on. In this context, it’s important to know that a person is contagious one or two days before the disease breaks out – leading to the risk that the person will spread the flu virus unwittingly.
When should we go for our flu vaccination?
The optimal time for getting a flu vaccination is between mid-October and mid-November. However, it can also be worth it later, even when the flu epidemic has already broken out. The vaccination lasts for about six months and needs to be refreshed every year.
How effective is the flu vaccination?
On average, those who are vaccinated fall ill with flu only half as often as those that don't take the vaccination. However, a vaccination doesn't provide the same level of protection every winter. Studies estimate effectiveness levels at 20 to 80 percent.
These fluctuations depend on several factors:
- Because influenza viruses change year after year, the vaccine has to be reconstituted each time, which is done in February for the following winter. This can result in people vaccinating themselves against something that is no longer circulating.
- The vaccination is not as successful for older people and people with chronic illnesses, i.e. those with weakened immune systems.
How willing are people to be vaccinated?
According to WHO guidelines, a vaccination rate of 75 percent would be advisable for risk groups. A recent CSS health study 2020 (in german) shows that the vaccination rate in Switzerland is much lower. Of the 4,217 people questioned, 18 percent said they get a flu vaccination every year. The majority of adults, 71 percent, do not get vaccinated at all. However, the willingness to be vaccinated depends on age: while 40 percent of those over 64 years of age have a flu vaccination every year, only 7 percent of 18 to 34 year olds do so.
Are other vaccination strategies required?
This is being discussed by the international scientific community. One of the approaches could be: instead of issuing a universal recommendation to older people, vaccinations can be given to as many children and young people as possible, as is practised in some European countries, including Finland. This is because the immune response is more pronounced in children. In addition, young people, especially school children, spread the virus more extensively through their numerous, close social contacts. The German consumer organisation Stiftung Warentest also recommends this approach, in contradiction to the advice issued by the Standing Committee on Vaccination at the Robert Koch Institute.
Can a flu vaccination trigger influenza?
The vaccines used in Switzerland contain inactivated virus components which cannot themselves cause influenza.
- However, 5 to 10 percent of those vaccinated may experience flu-like side effects such as fever, muscle pain or discomfort. The symptoms usually subside after one to two days.
- It also takes about two weeks before the vaccination takes effect. During this time it is possible to be infected with flu.
- It is also possible to catch a cold that isn't caused by influenza viruses, but is mistaken for the flu.
- Other side effects may be experienced, but are rare. These include hives, oedema, allergic asthma or severe allergic reactions (anaphylactic shock).
- Extremely rare are neurological disorders such as Guillain-Barré syndrome (one case per million vaccinated people).
How else can we protect ourselves from flu?
The simple rules of hygiene and conduct that also protect us from coronavirus are useful. They offer no guarantee of staying healthy, but can reduce the number of infections:
- Wash your hands thoroughly with soap and water several times a day. Don’t touch your face with unwashed hands.
- Hold a tissue in front of your mouth and nose when sneezing or coughing and dispose of it in the bin after use. Then wash your hands.
- When you don't have a tissue, sneeze or cough into your elbow.
- If you have flu symptoms, stay at home until you are fully recovered.
In most cantons people can now also be vaccinated against flu in a pharmacy. Many pharmacists have the required professional qualification. The vaccination pharmacies website features a list of all pharmacies offering a flu vaccination. CSS pays a share of the costs through the Health Account.