Influenza – rethink now for a new tomorrow

Viruses (from the Latin for poison, slime) have probably existed on this planet for over 3.5 billion years. A particular virus – the influenza virus – has been with humanity for a long time and has caused major pandemics such as the Spanish flu in the past. There are 3 subtypes: A, B and C.1 Influenza A and B are the most important pathogens for humans, since they trigger seasonal flu after infection.1

Other representatives, such as the corona virus, on the other hand, can trigger severe respiratory diseases and are currently determining large parts of public life worldwide.2 But viruses do not only have bad properties for us humans. In terms of evolutionary history, viruses are far more important to humans than it first appears.

Viruses as engines of evolution

After an infection with the influenza pathogen has survived, the human immune system adapts and a new infection becomes less likely. The influenza virus, on the other hand, is subject to antigenic drift because it lives by multiplying in the host. Due to the antigen drift, the surface protein haemagglutinin, which is recognized by our immune system, changes and reinfection is possible again.3

As a result, the human immune system and the virus are in a constant arms race. The human immune system improves due to the many variants, and it can also happen that viral genetic material is integrated into the human genome and can thus change the genetic material in small steps.4 As a result, about 8% of the human genome is made up of viral DNA that has wormed its way into our own genes over the course of evolution.5

Since viruses have been part of human history for a long time, they have always been of great interest, which has driven medical research forward. This knowledge helps us today to develop new medicines, vaccinations or therapies. In the COVID-19 pandemic, these findings are also helping humanity respond to new viruses. The new drugs, hygiene protection concepts and vaccinations were certainly responsible for the fact that the number of people who died from the coronavirus is lower than it was at the time of the Spanish flu. Although the number of people who died from the corona pandemic is enormous at 6.4 million6the Spanish flu claimed an estimated 20-100 million lives about 100 years ago.7

Influenza today and tomorrow

But how is the situation today? Both influenza and Sars-CoV-2 have not disappeared from our everyday lives. Rather, simultaneous infections with Sars-CoV-2 and influenza are possible and seem to promote a more severe course of infection.8 At the same time, however, the path to coexistence with the corona virus is the next desired step for mankind to be able to switch from a pandemic to an endemic situation.

Influenza and corona present with similar symptoms. However, the duration of infection and the risk of infection differ greatly. It therefore makes sense to differentiate between the two infections in order to be able to initiate appropriate protective and therapeutic measures and thus better protect the population. Although there have been no major waves of influenza, such as those that occurred every year before the corona pandemic, in the last two years, the number of infections in 2022 will rise sharply. This also increases concern about a severe course in the case of simultaneous infection.9,10

And now? What to do?

Vaccinations against the seasonal flu and also medicines, the antivirals, exist. These inhibit virus multiplication and thus support the immune system in the fight against the virus. A flu vaccination is particularly recommended for risk groups such as the elderly, the chronically ill or pregnant women, as it reduces the likelihood of severe courses and infection.11 The flu can also be treated according to the symptoms, which promotes the healing process.

For the individual, appropriate behavioral measures such as appropriate hygiene through thorough hand washing, disinfection and compliance with the sneeze label continue to be the most important everyday protection that everyone can carry out.

In practice, tests can be used to test for corona and influenza. The range of effective and sensitive rapid tests is constantly increasing, which enables medicine to make a quick decision and gives patients more security. In the event of a proven infection with the coronavirus, the patient can then go into quarantine or take other measures that follow the current recommendations. In the case of a proven influenza infection with an incubation period of only 1-2 days, however, bed rest is only prescribed in the acute phase of the disease.1,12

Interestingly, antivirals are rarely prescribed in practice, even though they are approved for the treatment of a viral infection. Since they are primarily induced for risk groups, they are less frequently prescribed to non-risk patients.13 Similar recommendations can also be found from the RKI with regard to influenza. Symptomatic treatment is recommended for patients who do not belong to the risk group or in whom no severe course is suspected.1 Especially in view of an impending double wave of corona and influenza, a rethink can help to alleviate the course of those affected, regardless of their risk status, and support the immune system in the fight against the virus.

Both medical knowledge and the immune system are supplied with new information for a healthier future. Even after many years of coexistence, humanity and the virus are still learning a lot from each other, and the immunological arms race is entering the next round. Sequel follows.

credentials

  1. https://www.rki.de/DE/Content/Infekt/EpidBull/Merkblaetter/Ratgeber_Influenza_saisonal.html
  2. https://www.tagesschau.de/ausland/coronavirus-tabelle-103.html
  3. https://www.rki.de/SharedDocs/FAQ/Influenza/FAQ_Liste_Virus.html
  4. https://www.museumfuernaturkunde.berlin/de/ueber/neuigkeiten/viren-krankheitserreger-und-beschleuniger-der-evolution
  5. https://www.spektrum.de/news/die-gute-seite-der-viren/1722318
  6. https://de.statista.com/statistik/daten/studie/1103240/umfrage/entwicklung-der-weltweiten-todesfaelle-aufgrund-des-coronavirus/
  7. https://www.br.de/wissen/gesundheit/krankheiten/spanische-grippe-influenza-virus-pandemie-106.html
  8. https://www.aerzteblatt.de/nachrichten/132928/SARS-CoV-2-und-Influenza-Kombinierte-Infektion-fuehrt-zu-schwereren-Verlaeufen
  9. https://www.welt.de/wissenschaft/article238035891/Grippe-Noch-immer-keine-Grippewelle-schwere-Folgen-befuerchtet.html
  10. https://influenza.rki.de/Wochenberichte/2021_2022/2022-27.pdf
  11. https://www.rki.de/SharedDocs/FAQ/Impfen/Influenza/faq_ges.html
  12. https://www.infektionsschutz.de/erregersteckbriefe/grippe-influenza/#c4375
  13. https://www.br.de/nachrichten/bayern/corona-medikamente-lang-erwartet-und-jetzt-doch-ladenhueter,T3T5Wfh

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