When you really feel awful

What is influenza (flu)?

The flu (medical term: influenza) is an acute viral infection that typically comes on quickly and spreads globally. It is one of the serious respiratory illnesses and can affect the whole body. It is characterised by a sudden onset with an abrupt feeling of illness. Because it occurs more often in the winter months, it is also called seasonal flu.

It is caused by influenza viruses, which are divided into different types. In particular, types A and B play a central role in humans. Type A is often responsible for large flu waves and is constantly changing genetically. Type B can also cause severe courses. Type C, on the other hand, usually causes only mild symptoms and appears more sporadically.

The virus is continually changing, which regularly produces new variants. This high capacity for change is a particular challenge because the immune system cannot always rely on antibodies that were previously formed. Even people who have had the flu before or who have been vaccinated are not automatically protected against future viral variants, as the pathogens can be genetically different.

How is the flu transmitted?

The flu is transmitted mainly by direct contact between people. This most often happens via tiny droplets released when coughing, sneezing or even speaking. These tiny particles contain viruses and enter the air, where they can be inhaled by other people in the immediate vicinity.

In addition to airborne transmission, contact with contaminated hands is an important route of infection. When virus‑containing secretions — for example from blowing the nose or touching the face — get on the hands, the pathogens can enter the body via the mucous membranes of the mouth, nose or eyes if one unconsciously touches the face.

Furthermore, contaminated surfaces play an important role in everyday life: door handles, grab rails on public transport or other frequently touched objects can carry viral particles. If such a surface is touched and the face is then touched, infection can also occur that way.

The time between infection and the appearance of first symptoms is usually one to four days. An infected person can infect others even before signs of illness are apparent.

What symptoms does the flu cause?

Influenza usually begins abruptly and is accompanied by a rapidly increasing physical exhaustion. Those affected often feel a clear sense of illness shortly after infection, accompanied by high fever, severe chills and intense headaches, muscle and limb pains. Also typical are a dry, distressing cough without phlegm, sore throat and a burning sensation in the throat. Sweating, loss of appetite and increased sensitivity to light or noise are also possible.

Additionally, a runny or blocked nose can occur, although it is usually less dominant. Children may also experience gastrointestinal symptoms such as nausea, vomiting or diarrhoea. Occasionally ear pain, rashes or croup‑like symptoms occur. In older people, the flu can present as disorientation or confusion, even if fever is absent.

The severity of symptoms varies from person to person: some develop a full set of complaints with fever, while others show only mild or no signs of infection.

How can vaccination protect against the flu?

An influenza vaccination significantly reduces the risk of severe influenza illness. While it may not prevent infection in every case, vaccinated people generally have a milder course of illness and are better protected against complications such as pneumonia, middle ear infection or myocarditis. The risk of serious secondary events such as heart attack or stroke is also reduced by vaccination.

How well the vaccine works depends on how closely it matches the viruses actually circulating. In young adults, protection can be up to 80%, while in children and adolescents it ranges between 59% and 75%. Older people often have a weaker immunological response to the vaccine but still benefit, with their risk of illness reduced by up to 63%. An adjuvanted vaccine is additionally available for them to improve the immune response.

Because influenza viruses continually change, the vaccine must be updated annually. Predictions about which strains will predominate in the coming season are based on worldwide surveillance. Despite production challenges, this approach prevents many illnesses and severe courses each year.

Flu or common cold?

The terms “flu” and “common cold” are often used interchangeably in everyday language, although they describe different conditions. A common cold typically develops gradually. It usually begins with a slight scratchy throat or blocked nose and is mostly mild. Many different types of viruses are responsible and they usually cause only moderate symptoms.

By contrast, influenza, the “true flu”, is caused by specific influenza viruses. This disease is characterised by a sudden onset with very pronounced symptoms such as high fever, intense limb pains and severe exhaustion. The duration of symptoms is also usually longer than with a common cold.

Another difference is the severity and medical significance: while a cold is usually mild and clears up within a few days, the flu can heavily burden the body and, in some cases, cause serious complications. There is a targeted vaccine against influenza — for colds this is not possible because of the large number of different causative agents.

Who should get vaccinated against the flu?

An influenza vaccination is particularly recommended for people at increased risk of severe illness. These include people aged 60 and over, people with chronic conditions such as diabetes, asthma or cardiovascular disease, people with a weakened immune system and pregnant women. For pregnant women, the timing of vaccination depends on health status and the week of pregnancy.

Children from six months of age with certain pre‑existing conditions, for example of the lungs, heart, liver, kidneys or with neurological disorders, should also be vaccinated annually as they are particularly susceptible to complications. In addition, people who frequently come into contact with many others benefit from vaccination, such as healthcare personnel, educational staff or public transport workers.

Vaccination can also help protect vulnerable relatives indirectly in the personal environment — for example older or ill family members — by reducing the spread of the virus.

How to treat the flu: helpful tips

• Stay in bed for at least two full days, even if you feel better. The body needs not only rest to support the immune response but also time to recover. Getting up too early increases the risk of relapse.
• Set up a recovery corner. Put several blankets, warm socks, a hot water bottle and everything important like tea, medication and tissues within easy reach to avoid unnecessary trips.
• Drink targeted herbal teas depending on the symptom: chamomile for throat inflammation, thyme for cough or lime‑blossom or elderflower tea for fever. Prepare the tea fresh, let it steep for ten minutes and drink it in small sips.
• Inhale hot steam with a little chamomile or salt two to three times a day. Hold your head over a bowl, cover it with a towel and breathe in through your nose and out through your mouth. Repeat the procedure for 10 minutes each time.
• Apply warm potato compresses for sore throat. Boil two potatoes, crush them with the skin in a cloth, let the cloth cool to a comfortable temperature and place it on the neck for 20 to 30 minutes.
• Make onion syrup yourself: chop an onion finely, add two tablespoons of honey or sugar and leave the mixture for several hours. Take a teaspoon of it several times a day.
• Gargle three to four times a day with lukewarm salt water (1 tsp salt in 250 ml water). This soothes sore throat, reduces swelling and inhibits germ growth in the throat.
• Ensure regular fresh air supply: ventilate the sickroom hourly for five to ten minutes by airing widely to lower the viral concentration in the air and relieve the mucous membranes.
• Keep the room air humid by placing a bowl of water on the heater or a damp towel over the radiator. A humidity of 40–60% prevents the mucous membranes from drying out.
• Use a decongestant nasal spray if needed. Use it only in the evening to help sleep, and no longer than five days to avoid dependence.
• Drink two to three litres of fluid daily. In addition to water, warm broths, herbal teas or hot water with freshly squeezed lemon juice are suitable. This compensates for fluid loss and keeps the mucous membranes moist.
• Cool your forehead with a damp washcloth for high fever. Dip it in cool but not ice‑cold water, wring it out and place it on the forehead for 10 to 15 minutes.
• Keep your sleeping position elevated if your nose is blocked. Place two pillows on top of each other or use a wedge pillow. This allows secretions to drain better and makes breathing easier.
• Eat vitamin‑rich, easily digestible foods. Opt for warm vegetable soups, grated apples, ripe bananas or steamed vegetables. These are gentle on the stomach and provide important micronutrients for the immune defence.
• Get vaccinated in time if you belong to the risk groups — flu vaccines reduce the risk of complications from this winter infection that often occurs with headaches and other illnesses. If symptoms occur, consult a doctor promptly.

A true influenza can heavily burden the body and should not be taken lightly. Those who respond in time and listen to their body can support the healing process.