Preventing flu: how to protect yourself against flu viruses

The flu (also known in medical terms as influenza) is a highly contagious respiratory illness. It is triggered by influenza viruses, which multiply in the mucous membranes of the respiratory tract, where they destroy cells. The body reacts with pronounced inflammation of the mucous membranes.

Experts differentiate between different types of viruses, with influenza A and influenza B causing the most common illnesses. Because flu viruses are constantly changing, neither having already had the flu nor getting a flu vaccination provides lasting protection.

The flu virus is easily transmitted. Flu viruses pass from one person to another primarily through an airborne infection. When an infected person coughs and sneezes, droplets containing the virus are released. Infection via contact transmission is also possible: flu viruses often end up on our hands and are therefore transferred to door handles or handrails. This allows them to spread to other people. Flu viruses are also transmitted through direct contact, such as handshakes. Cold, dry air helps the viruses to spread more quickly. 

The incubation period for flu viruses, meaning the time between infection and the first symptoms, is one to four days. An infected person can even pass on the virus one day before their first symptom appears. Even after the flu symptoms subside, a person usually remains contagious for up to a week.

The flu virus is easily transmitted. Flu viruses pass from one person to another primarily through an airborne infection. When an infected person coughs and sneezes, droplets containing the virus are released. Infection via contact transmission is also possible: flu viruses often end up on our hands and are therefore transferred to door handles or handrails. This allows them to spread to other people. Flu viruses are also transmitted through direct contact, such as handshakes. Cold, dry air helps the viruses to spread more quickly. 

The incubation period for flu viruses, meaning the time between infection and the first symptoms, is one to four days. An infected person can even pass on the virus one day before their first symptom appears. Even after the flu symptoms subside, a person usually remains contagious for up to a week.

The flu starts suddenly. You might feel fine in the morning, but a few hours later you suddenly develop a fever and chills. The symptoms are usually more severe than those of a cold and affect the entire body.

The most common flu symptoms include:

• A fever between 38°C and 40°C or even higher
• Severe headaches
• Aching muscles and joints throughout the body
• Sore throat and dry cough
• Chills
• Severe exhaustion and feeling very unwell
• A blocked or runny nose
• Loss of appetite

Flu symptoms are not always accompanied by a fever. Many people with the flu develop typical complaints such as sudden onset of aching limbs and muscles, severe tiredness or a cough. Others only have mild symptoms similar to a cold. Some infected people don’t even notice the infection. 

Flu: duration and progression

The most severe flu complaints usually subside within the first week. However, a cough and exhaustion often last longer. In total, the flu lasts up to two weeks. Children often experience additional symptoms including nausea and vomiting.

A severe case of the flu with complications such as pneumonia often affects high-risk groups, which include pregnant women, people over the age of 60 and people with chronic illnesses or a weakened immune system. A very severe case can be life-threatening for these groups of people. It is therefore advisable to consult a doctor in such cases.

If you do not fully recover from a case of the flu, this can sometimes have health consequences, including prolonged inflammation of the sinuses or, in children, an inflammation of the middle ear. Sufficient rest and recovery are therefore especially important.

There is no way to ensure complete protection against the flu. However, with good hygiene and a healthy lifestyle, you can reduce the risk of infection. The following measures will help protect you from the flu.

Preventing flu with good hygiene

If you want to prevent infections with flu viruses, you should observe basic hygiene rules in your daily life. These include:

• Wash and disinfect your hands: wash your hands regularly with soap and warm water for 20 to 30 seconds. Apply soap to the palms of your hands, the backs of your hands, your fingertips, the spaces between your fingers and your thumbs. Dry your hands thoroughly after washing. Pathogens can reproduce particularly well on moist skin. In public spaces, disposable towels are usually the most hygienic option.
• Avoid touching your face: take care not to touch your face. Most viruses are transmitted via the hands. Pathogens enter the body via the mucous membranes in the mouth, nose and eyes.
• Avoid coughing or sneezing into your hands: sneeze or cough into a tissue, dispose of it afterwards and wash your hands. If this is not possible, sneeze into the crook of your arm. This is more hygienic than coughing or sneezing into your hands.
• Ventilate regularly: open the windows wide for a few minutes several times a day. Fresh air dilutes the concentration of viruses in enclosed spaces and reduces the risk of an airborne infection.
• Clean surfaces: door handles, light switches and other frequently touched objects transmit flu viruses via contact transmission. Clean these surfaces regularly.
• Avoid crowds: flu viruses spread particularly easily in enclosed rooms with large numbers of people, especially during a flu outbreak. During flu season, it’s advisable to avoid large gatherings of people. Because the pathogens are transmitted by droplets and aerosols, masks can protect you and others from infection. Aerosols are solid or liquid particles that float in the air. They are produced when we breathe, talk, cough or sneeze, but can also be caused by dust or smoke.

In a shared household, it’s a good idea to pay particular attention to hygiene at the first signs of illness, to avoid infecting your children, flatmates or partner with the flu. 

Strong defences: nutrition, exercise and sleep

A healthy lifestyle that includes plenty of exercise, a balanced diet and enough sleep can strengthen the immune system, reducing the risk of infection. These habits will help you prevent the flu:

• A balanced diet: eat fresh fruit and vegetables. The minerals these contain such as copper, folic acid, iron, selenium, amino acids and omega-3 fatty acids contribute to the normal functioning of the immune system. Vitamins also play a role in preventing the flu – in particular vitamin A, vitamin B6, vitamin B12, vitamin C and vitamin E support the normal functioning of the immune system.
• Plenty of exercise in everyday life and fresh air: regular exercise gets your circulation going and strengthens your immune system. You should therefore get out in the fresh air regularly. A walk, a bike ride or a short workout is all you need.
• Get enough sleep: sleep seven to eight hours a night. Restful sleep at regular times supports your immune system. Avoid light from smartphones and tablets in the evening, as the high proportion of blue light disrupts the production of the sleep hormone melatonin.
• Indoor climate and mucous membranes: moist mucous membranes are better able to defend against viruses. Dry heated air puts a strain on the airways and makes it easier for pathogens to penetrate. Drink plenty of water or unsweetened tea and ensure regular ventilation to create a good indoor climate.

Preventing flu with medication and home remedies

Medications are not suitable for preventing flu in the general population. In specific high-risk situations, antiviral medication can be used preventatively.

For an active infection, however, prescription antiviral drugs are available. These remedies shorten the duration of the illness by about one day or occasionally lead to milder symptoms – but only if taken within the first two days of the onset of symptoms. 

Many people use home remedies to combat flu and colds such as herbal teas or chicken broth. There is no scientific evidence that such measures can speed up recovery, although they can relieve symptoms. Even over-the-counter vitamin supplements or inhalers have so far shown no convincing effects against the flu.

Flu season is usually during the cold season from December to March. During this time, influenza viruses circulate particularly widely and cause a flu outbreak practically every winter in many places, including Switzerland. The intensity and severity of seasonal flu vary from year to year.

As flu season approaches, it’s worth taking precautions in good time. The best protection is the annual flu vaccination. You can also boost your immune system with a balanced diet, regular exercise and good hygiene. This helps to reduce the risk of infection and protect yourself and others.