Flu (influenza)

The flu is anything but harmless. It is a viral infection that can cause serious complications and can be life-threatening. More in the guidebook flu.

Flu (influenza)


Flu, influenza, real flu


Woman with flu

Many people consider influenza a serious form of cold. At first glance, the symptoms of influenza really do not differ from those of a cold or a flu infection. But what is the flu? Influenza is a respiratory infection that is transmitted by the flu virus - also known as the influenza virus. Influenza - unlike most colds - can be very severe and even fatal. For example, in the flu season 2015/2015, the flu caused more than 6 million visits to the doctor and more than 31,000 hospital admissions. Health insurance funds, Robert Koch Institute and medical societies warn year after year. Almost prayer-like - and with modest success: especially risk groups should be vaccinated against the flu.


This year, the flu epidemic gained momentum late. In the weeks since the beginning of 2018, the frequency is steadily increasing. The RKI reports 24,264 confirmed influenza cases for the 7th week. Last week it had been 18,714. Particularly affected are the south and the east of Germany. But you should not feel safe even in the middle. Doctors from the Rhine-Main region or the health department of Frankfurt say that the flu epidemic sometimes leads hospitals and medical practices to the limits of resilience. At least 102 people have died of influenza so far.

According to the RKI, nearly 75 percent of influenza infections are caused by influenza B viruses from the Yamagata line. Therefore, people who are vaccinated with a triple vaccine against influenza, currently have only a very low level of protection. In contrast, quadruple vaccines also protect against these influenza B viruses.

During the flu season 2016/2017, the Robert Koch Institute has registered a total of more than 112,000 confirmed influenza infections. In 662 confirmed cases, influenza was fatal. The dark figure is likely to be significantly higher. For example, for the flu season 2014/2015, experts predict more than 20,000 deaths. Not all of these people are dying directly from the flu. However, the infection weakens so much that other diseases lead to death.


Typical symptoms include fever, chills, cough, runny nose, body aches, sore throat, hoarseness, headache and fatigue. But they are usually more difficult than a cold and take longer. After a flu, you usually feel tired and chipped for a long time.

The flu can be complicated

From the more or less harmless flu symptoms caused by spread of viruses and additional bacterial infection often serious diseases. These include tonsillitis, otitis and sinusitis.

Dreaded complications include pneumonia and meningitis. These complications are responsible for most of the deadly courses of the flu. Particularly vulnerable are older and weakened people.

Recent studies show that children and adolescents between the ages of 10 and 19 as well as young adults (up to 25) have recently disproportionately had flu.


Influenza is caused by influenza viruses. Since these viruses are constantly changing, one is after a surviving flu not immune to further infections, as is the case with other viral diseases. The rapid variability of influenza viruses is also the reason why a flu vaccine is only effective for the current season.

The flu season starts in October

Colds and flu are particularly common from October to March. But that has little to do with cold weather and bad weather. A much bigger role plays the air dryness. Influenza viruses survive significantly longer in dry cool air than in heat or high humidity. Therefore, they multiply faster in the winter months than at other seasons. At the same time, influenza viruses have an easier time in the winter to penetrate our body through our mucous membranes. Because of the harsh winter weather and heating air, the mucous membranes are less resilient and drier than at other times. In addition, during the cold and humid months we often stay in closed rooms. This significantly increases the risk of droplet and smear infections with the influenza virus (see also Causes).

Transmission of influenza viruses

The flu is transmitted by droplet infection. That is, you inhale the viruses that enter the air from an infected person when coughing or talking. Dry room air in heated rooms favors the transmission.

Another possibility of transmission is the lubrication or contact infection.The viruses are very easily with the smallest amounts of nasal secretions or some moisture from the hand, which has been kept to the mouth when coughing, on cups or doorknobs. And then transferred to the own mucous membrane via the hands. One of the most common sources of infection is consequently the handshake.


For severe flu symptoms you should go to the doctor. This is especially true for pregnant women, infants, toddlers and elderly, weakened people or persons with impaired immune systems. In addition, a visit to a doctor is recommended for signs of complications. For example, in case of high fever, shortness of breath, earache or a strongly reddened mucous membrane as an indication of a sore throat.

In the first 48 hours of flu, the symptoms can be dampened with medication. In the case of an additional bacterial infection, the doctor may also prescribe antibiotics. Your doctor may recommend over-the-counter medications and home remedies to treat flu symptoms such as fever, cough, runny nose, and pain.

According to a study, the antiviral drug Tamiflu can reduce the duration of spleen by one day.

Self-help and home remedies for the flu

Home remedies for the flu and over-the-counter medications can significantly relieve the symptoms. Appropriate suggestions can be found in the guidebooks fever, cough, runny nose, hoarseness, sore throat and fatigue.

Especially for children, the elderly and people with chronic diseases, an exclusive self-treatment of influenza is by no means recommended. This is especially true because flu is not always recognized as a flu, but is confused because of the very similar symptoms with a cold.


The best protection against flu offers a vaccination. More about that right now. For all those for whom a vaccine is definitely not possible or not possible, the protection against smear and droplet infections is especially recommended. One of the most important means: regular hand washing.

Avoid smear infections

Almost all smear infections with the influenza virus happen over the hands. The viruses, for example, when snuffling or coughing on the hand, from there on doorknobs or cups - and to other people.

Avoid droplet infections

The risk of droplet infection during a flu episode is easiest to reduce by avoiding large crowds. This is less true for outdoor events, but rather for rooms with dry air. Dry air and dry mucous membranes significantly increase the risk of infection. Respiratory masks provide a certain protection, as they are often seen in the cities of Asia in cinemas or department stores.

Do not distribute influenza viruses

The most important non-medical precautionary measure is to stay in bed with the flu and recover. A significant part of the flu infections are caused by sick people going to work or playing sports. And exposing many other people to the risk of infection. At the latest at the onset of the first flu symptoms you should do yourself and your loved ones the favor of not carrying the flu further than they already get with the flu epidemic.

And two helpful tips to stop spreading flu viruses.

  • Use disposable handkerchiefs. As the name suggests, really only for a Schneuzer - and dispose of the used paper tissues in the trash, if possible in a small plastic bag packed.
  • Do not hold your hand over your mouth and nose when sneezing or coughing. It is better to sneeze or cough in the crook of your arm. So you keep the virus with you and do not pass it on your hands unintentionally.

The best protection: the flu shot

Undoubtedly, the flu vaccine offers the best possible protection against influenza. Nevertheless, according to the Robert Koch Institute (RKI) only a good 30 percent of adults in Germany are vaccinated against influenza. An RKI survey of people over 65 and chronically ill from 2015 provides the key answers to the question of why. More than half of respondents believe that the flu vaccine can trigger the disease itself. And: Many of the interviewees consider the flu to be as harmless as a cold. Both assumptions are wrong: Influenza vaccination leads only in very rare cases to a flu infection. Rather, it usually comes by accident to a slight cold, just because vaccinated in the cold season. This is then pushed on the vaccine and confused with a flu.

Although the flu and cold have similar symptoms, they are very different. Also possible vaccination reactions can occur. Fatigue, muscle aches and shivering after a flu shot are quickly considered flu. However, unlike a true influenza vaccination reactions disappear after 1 to 3 days.

Flu vaccine 2017/2018

The flu is so hard to fight because the flu viruses change year by year. This makes it hard to fight for the immune system - and the vaccines also need to be adjusted annually.The World Health Organization (WHO) is tracking changes in influenza viruses worldwide and using its analyzes to make recommendations on how to vaccinate influenza strains in their respective regions of the world.

The vaccines for the 2016/2017 flu season in Europe, according to the WHO recommendation, contain the following antigen strains:

  • Triple vaccines (trivalent vaccines) against the influenza virus strains A / Michigan / 45/2015 (H1N1), A / Hong Kong / 4801/2014 (H3N2) and B / Brisbane / 60/2008
  • Quadruple vaccines (quadrivalent vaccines): in addition B / Phuket / 3073/2013.

The cost of trivalent flu vaccines are usually covered by the statutory health insurance. In contrast, quadrivalent vaccines are non-reimbursable in almost all cases and must be paid out of pocket.

vaccination recommendations

The RKI Standing Vaccination Commission recommends influenza vaccination primarily for all people over 60, residents of nursing homes, the chronically ill, weakened immune systems and for people who are frequently exposed to influenza viruses (medical staff, salesmen, flight attendants, etc.). ).

According to RKI, healthy pregnant women should be vaccinated at the latest in the second trimester of pregnancy, pregnant women with chronic illnesses and / or a weakened immune system already at the beginning or in the first third of the pregnancy.

The RKI recommends another vaccination recommendation for people who are in contact with poultry and wild birds in order to avoid double infections with influenza and avian influenza.


The vaccine protection of the flu vaccine can unfortunately not be predicted accurately. One of the reasons is that influenza viruses may have changed in the period between production of the vaccine and the onset of the flu epidemic. In addition, the immune system of the vaccinated plays an important role in the defense against influenza viruses. Generally speaking, the vaccine should prevent about half of the infections, sometimes more, rarely less. At the same time, in most cases vaccination ensures that flu infections are significantly less pronounced.

Vaccination schedule

For the flu vaccine, a single vaccination is sufficient. The vaccine protection starts between 10 and 14 days after vaccination. The ideal time is October or November. The flu shot is also worthwhile at any other time of flu epidemic, especially at an individually increased risk.


People should not vaccinate with fever and severe acute infections. The flu vaccines are cultivated on egg white and therefore contain corresponding traces. In case of an allergy to chicken protein, the vaccination should therefore be individually coordinated with the attending physician. Live vaccines should also not be administered in immunocompromised (immune deficiency) or severe asthma.

Side effects of the flu shot

Typical side effects of influenza vaccination are usually limited to local reactions at the injection site such as redness, itching, swelling or burning. Occasionally, live attenuated influenza virus vaccines cause cold-like symptoms with runny nose, fever, chills, fatigue, headache, muscle aches, or pains in the limbs.

All important questions about influenza vaccination are answered in the special topic: 15 Frequently Asked Questions and Answers to the Flu Shot.

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