Interesting facts and helpful tips about flu

Influenza Unveiled: Everything You Need to Know

Woman with flu sits on the couch wrapped in a blanket and blows her nose. Woman with flu sits on the couch wrapped in a blanket and blows her nose.
Every year, millions of people around the world fall victim to the influenza virus. But why do we repeatedly witness new flu waves, and why do they happen around the same time each year? How does flu differ from the common cold, and what measures can we take to protect ourselves? In this article, we shed light on these questions!

Flu vs. cold: Decoding the culprit

Ever experienced a scratchy throat and sudden discomfort, and wondered whether it’s the flu or just a common cold? The infections are often confused with each other due to their similar symptoms, yet there are key differences. The most important difference is the type of pathogen: while a cold can be triggered by many types of viruses (e.g., adenoviruses, enteroviruses, or rhinoviruses), the flu has its "own" pathogen: the influenza virus.

There are multiple subtypes of this virus. For instance, you might have heard of the influenza type H1N1, responsible for the infamous Swine Flu which first emerged in 2008. The letters represent the proteins hemagglutinin (H) and neuraminidase (N), which help the virus penetrate the body’s cells and escape after proliferation [1].

However, there are also other influenza subtypes, such as the Yamagata and Victoria lineages. Viruses from the Victoria lineage cause illness in children, in particular those between the ages of 5 and 14. Yamagata viruses, on the other hand, tend to affect people aged 35 and over. However, since March 2020 this lineage has no longer been detected [2].

Microscopic representation of individual viruses.

Flu vs. cold: The symptoms

Despite superficial similarities, on closer inspection the symptoms of flu and cold actually differ. The flu usually strikes suddenly. Just a moment ago you felt perfectly healthy – then, all of a sudden, you're plagued by a sore throat, headache, and aching limbs, as well as a dry cough and general exhaustion. A high fever often sets in, too [3].

The common cold usually creeps in gradually. It starts with a mild sore throat and then develops to include a cough, runny nose, and mild muscle pain. Compared to the flu, a cold’s symptoms are generally less severe [4].

The course of both the flu and the common cold can vary from person to person, but symptoms usually persist for 7 to 10 days, symptom relief can be expected after 5 to 7 days. Additionally, flu symptoms can vary greatly from person to person. Some will show no symptoms at all, others present similarly to having a cold, and the remainder experience the full intensity of flu’s characteristic symptoms [5].

A woman with flu lies on the couch and looks at a fever thermometer.

Yearly recurrence: The flu season

A crowded café.

Most influenza viruses circulate in the northern hemisphere between October and early May, marking the flu season. That’s why many countries closely monitor infection rates. In Germany, for example, samples from patients with respiratory diseases are regularly examined. As soon as influenza viruses are detected in every fifth sample, there is officially a flu epidemic [6].

But why does the flu spread predominantly in winter and spring? One of the main reasons is that influenza viruses are more stable at low temperatures and in dry air. Experts also believe the immune system is less effective in winter and that the mucous membranes of the upper respiratory tract are more susceptible to infections in dry air [7]. Add to this the fact that people spend more time indoors in colder temperatures, creating even more favorable conditions for transmission.

The flu virus: A real master of disguise

The yearly impact of flu outbreaks depends largely on genetic changes in the virus and whether virus variants are in circulation. Influenza viruses, or the individual subtypes, are particularly prone to such mutations [8].

Mutations, essentially copying errors during genetic replication, often affect the protein haemagglutinin, which enables the influenza virus to penetrate the body’s cells. The more the protein changes due to the mutation, the more difficult it becomes for the immune system to recognise the invaders and react to them – even if it has already fought flu viruses in the past [9].

This explains why flu outbreaks tend to be more severe when a new virus variant is in circulation: Our bodies and immune systems are, simply put, not prepared for the "new" pathogen. Consequently, the flu vaccine is evaluated and potentially adjusted each year to match the circulating variants.

Protecting yourself from the risk of infection

You probably already know that flu viruses, like some other viruses, are mostly transmitted via aerosols in the air. Infection, therefore, usually occurs via inhalation of the pathogens. However, the viruses also survive on surfaces and can also enter the body via the hands and mucous membranes [10]. If you want to reduce the risk of getting sick, you have various options.

Even kindergarten children today know that regular hand washing is a sensible measure to protect themselves from illnesses such as the flu, as it eliminates a significant proportion of pathogens. It has become a natural thing for many people nowadays to wash their hands thoroughly in many situations, for example after coming home, before eating, or after coming into contact with potentially infectious material.

However, frequent washing with soap and water also has a side effect: it can stress the skin and lead to irritation and inflammation. A practical alternative is hand disinfectants such as Sterillium® foam extra care, which actively cares for and protects your skin with the help of ingredients such as vitamin E and jojoba oil.

Moreover, hand disinfectants provide a convenient solution for on-the-go situations where handwashing may not be feasible – for example, when you're on the subway or shopping in the supermarket.

Application of Sterillium® foam extra care.
During the coronavirus pandemic, we learned social distancing is a sensible way to break chains of infection. Even during the flu season, it helps to avoid or limit contact with large crowds and sick people wherever possible. Additionally, you should also stay at home yourself if you notice flu symptoms.
Two people stand opposite each other, a white line indicates the distance they must keep.

Getting vaccinated each year is another option to steer clear of the flu. While the vaccine doesn't prevent infection per se, it supports the immune system in preparing for the virus's potential entry through the air or mucous membranes.

In essence, the vaccine comprises of inactivate viruses which are unable to trigger a "real" flu infection, but are still perceived by the body as pathogens. The immune system reacts accordingly, producing an immunological memory that can be better able to fight the invaders in the event of a future infection. The vaccination teaches the immune system how it should react to flu viruses and thus can protects you in the event of an infection from these pathogens.

A woman getting vaccinated.

Home remedies that can help with the flu

There is no such thing as 100% protection against the flu, so it is possible to contract the virus despite taking all necessary precautions. If this is the case, you should see your doctor. There are also some tried and tested home remedies that can help to alleviate annoying symptoms and cure the illness in the best possible way:

  1. Fluids: your body needs plenty of fluids, especially when you are ill. Make sure you drink enough, preferably 2-3 litres a day.
  2. Tea: A sore throat can usually be soothed with chamomile, sage, or ginger tea.
  3. Nasal irrigation: If you have a really annoying runny nose, nasal irrigation with salt water can help clear your airways.
  4. Inhalation: Inhaling hot steam can also improve breathing. Additives made from chamomile, eucalyptus or thyme are particularly beneficial.
  5. Rest: Refrain from strenuous activities during the illness and, ideally, for a few days after the symptoms have subsided, too. Give your body the time it needs to recover.
A cup of ginger tea with ginger roots next to it.

Sources:

[1] Robert Koch Institut / Virus und Erkrankung
https://www.rki.de/SharedDocs/FAQ/Influenza/FAQ_Liste_Virus.html#FAQId8299000

[2] Robert Koch Institut / Grippesaison und Grippewelle
https://www.rki.de/SharedDocs/FAQ/Influenza/FAQ_Liste_Grippesaison.html

[3] AOK.de / Grippe oder Erkältung – das ist der Unterschied
https://www.aok.de/pk/magazin/koerper-psyche/immunsystem/das-ist-der-unterschied-zwischen-grippe-und-erkaeltung/

[4] AOK.de / Grippe oder Erkältung – das ist der Unterschied
https://www.aok.de/pk/magazin/koerper-psyche/immunsystem/das-ist-der-unterschied-zwischen-grippe-und-erkaeltung/

[5] Robert Koch Institut / Influenza
https://www.rki.de/SharedDocs/FAQ/Influenza/FAQ_Liste.html

[6] Robert Koch Institut / Grippesaison und Grippewelle
https://www.rki.de/SharedDocs/FAQ/Influenza/FAQ_Liste_Grippesaison.html

[7] Robert Koch Institut / Grippesaison und Grippewelle
https://www.rki.de/SharedDocs/FAQ/Influenza/FAQ_Liste_Grippesaison.html

[8] Robert Koch Institut / Grippesaison und Grippewelle
https://www.rki.de/SharedDocs/FAQ/Influenza/FAQ_Liste_Grippesaison.html

[9] Robert Koch Institut / Grippesaison und Grippewelle
https://www.rki.de/SharedDocs/FAQ/Influenza/FAQ_Liste_Grippesaison.html

[10] Infektionsschutz.de / Grippe (Influenza)
https://www.infektionsschutz.de/erregersteckbriefe/grippe-influenza/


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