Influenza (“the flu”)

The flu usually affects the entire body rather than just the airways. It often starts quickly with quite severe symptoms such as fever, pain and fatigue. But only about one-third of people who get the flu have these symptoms. The symptoms could also be milder or less typical, and might resemble those of a cold. Another third of those who get the flu don't even notice it.

The symptoms of the flu include:

• A fever between 38°C and 40°C (about 100-104°F) or higher
• Muscle and joint pain throughout the entire body (myalgia and arthralgia)
• Headaches
• Sore throat
• Chills
• Severe fatigue and a general feeling of being very ill
• Dry cough
• Stuffy and/or runny nose
• Loss of appetite
• Extreme tiredness

Nausea, vomiting and fever are also possible in rare cases.

If you have flu-like symptoms, it may be a good idea to go to the doctor. This is especially true for people who have a higher risk of complications.

The way the flu develops over time can vary. It is not possible to predict how it will develop based on the initial symptoms. Even if the symptoms are mild at first, the flu can get worse later on and lead to complications.

The first symptoms usually appear one to two days after you've been infected with the flu virus. The worst is usually over after the first week. But it can take a little longer for the symptoms to go away completely. A cough in particular can be stubborn. It might take up to two or three weeks for it to clear up.

Sinusitis (an inflammation of the sinus cavities) is one very common complication of the flu. That is when the cavities surrounding the nose fill with fluid and mucus. Common symptoms of sinusitis include a headache and a stuffy nose. In children, middle ear infections are common.

In rare cases, the flu can become more serious and lead to complications like pneumonia. That is influenced by your general health and which flu viruses are circulating. Other possible complications include inflammation of the heart muscle (myocarditis) or brain (encephalitis). It will often become apparent if the flu is getting worse after three to ten days. People who have a weakened immune system are particularly at risk of developing severe illness with complications, for example:

• People over the age of 60
• Babies and toddlers
• Pregnant women in their last trimester
• People with chronic conditions such as asthma, COPD, cardiovascular disease, diabetes, liver or kidney disease, multiple sclerosis, or HIV

Flu viruses are spread by means of droplet infection: When someone who is infected coughs or sneezes, droplets containing the viruses are released into the air -especially during the first few days. The droplets are then breathed in by other people or they settle on objects. Viruses also get onto the tissue and your hands when you blow your nose. They are easily spread from person to person wherever a lot of people touch the same objects, like doorknobs or handrails on the subway or a bus. Cold and flu viruses are also spread through direct contact, such as shaking hands or hugging.

These viruses need to be transferred from your hands to your eyes, mouth or nose for you to become infected. That can easily happen when you touch your hand to your face.

The most effective way to protect yourself and others from flu viruses is to stop them from spreading by:

• Carefully washing your hands thoroughly with soap
• Coughing or sneezing into your elbow or a tissue, and not into your hands
• Touching your face as little as possible
• Regularly letting fresh air into the room
• Throwing away used tissues
• If you have cold symptoms, try to have as little contact with others as possible, especially for the first few days.

A mask that covers your mouth and nose can help to stop the viruses from spreading.

A flu vaccination can also help to effectively protect you from flu viruses. Flu shots are offered every fall, primarily to people who have a higher risk of complications.

If you have the flu, it's most important to first get some rest until the symptoms go away. Doctors recommend drinking plenty of fluids, especially if you have a fever or cough.

Many people turn to home remedies like chicken broth, herbal teas or steam inhalation to relieve their flu symptoms or simply because it makes them feel better. But there's no scientific proof that any of these things helps speed up recovery. So you don't necessarily have to use any of these remedies or drink more fluids than you feel like drinking.

Painkillers such as acetaminophen (paracetamol), acetylsalicylic acid (ASA, the drug in medicines like Aspirin) and ibuprofen can relieve pain and reduce the fever.

You can use a decongestant nasal spray or nasal drops for a few days to relieve a stuffy nose. To stop the urge to cough, you can do things like drinking to keep your throat moist and avoiding triggers like dry air or smoke. You could also try herbal remedies, like ivy leaf, thyme or primrose root extracts.

Besides these over-the-counter options, special flu medication is also available. It is an option for people with the flu who have an increased risk of serious complications. Flu medication is intended to shorten the duration of the illness. In Germany, oseltamivir (brand name: Tamiflu) and zanamivir (brand name: Relenza) are commonly used. Oseltamivir is prescription-only and should be taken within two days after the flu starts.

Antibiotics are only effective against bacteria, not against flu viruses. So antibiotics can only help if you have a bacterial infection of the airways as well as a viral infection. Unless there are signs of bacterial infection, there's no point in taking antibiotics.

When people are ill or need medical advice, they usually go to see their pediatrician or family doctor first. Information about health care in Germany can help you to navigate the German healthcare system and find a suitable doctor. You can use this list of questions to prepare for your appointment.

The Robert Koch Institute has listed answers to frequently asked questions about the flu on its website (in German).