Influenzavirus

Vaccination: The active vaccination against influenza contains a tri- or tetravalent dead vaccine (2 A strains plus 1-2 B strains. The vaccination must be repeated annually, as the vaccine is adapted to the recommendations of the WHO in each case, so that the antigen composition corresponds to the current epidemic strains.

The protection rate of vaccination is about 60% in patients < 65 years of age; the protection rate is lower in the elderly. The mortality rate in people > 60 years has been shown to be reduced by vaccination. However, exact figures on this vary widely in the literature. There is also evidence that vaccination reduces cardiovascular mortality (apoplexy, myocardial infarction).

The nasal attenuated vaccine available for children and adolescents from 2 to 18 years of age is not effective against A/H1N1 viruses.

Sufficient protection for the patient is available approximately 14 days after vaccination.

Until now, it was said that the active ingredient of the vaccination only lasts 3-4 months and therefore one should not be vaccinated too early. November was recommended as the optimal time, since typically the peak of the disease falls at about the beginning of February. There are now manufacturers' claims that the vaccine effect is 6 - 12 months.

Indications for vaccination:

- generally all persons > 60 years

- persons with congenital, acquired or drug-induced weakening of the immune system

- Persons with cardiopulmonary diseases

- pregnant women

- Persons with increased exposure

- persons exposed to direct contact with birds and / or wild birds (here there is no protection against avian infection, but against double infection)

- in case of epidemics ALL patients should be vaccinated

Contraindications to vaccination:

- patients who are acutely ill with a febrile infection

- Persons with egg white allergy (in this case a chicken egg white free vaccine is available)

Side effects of vaccination:

Occasionally mild general reactions occur such as.

- pressure pain at the injection site

- Chicken protein allergy (rare)

- Vasculitis (very rare)

- Thrombocytopenia (very rare)

- Guillain-Barré syndrome (1:1 million)

- Narcolepsy after vaccination against swine flu (very rare)

The influenza virus is an RNA virus of the orthomyxovirus family. Based on the two antigens nucleoprotein (NP) and matrix antigen (M) located inside the virus, the virus is divided into the 3 types A, B and C. The types A and B are morphologically similar.

The Influenza A virus is classified as influenza A virus because of the glycoproteins:

- haemagglutinin (H) and

- neuraminidase (N) into further subtypes.

Haemagglutinin (H) is rod-shaped and enables attachment to the host cells.

The neuraminidase (N) has the shape of a fungus and causes the release of the viruses from the infected cells and also their spread in the respiratory tract.

In the meantime, 18 H-subtypes and 9 N-subtypes are known. However, so far only 6 H-types (H1, H2, H3, H5, H7, H9) and 3 N-subtypes (N1, N2, N7) have been detected in human epidemics. However, other subtypes can occur at any time.

The designation of new subtypes depends on

- Type

- first site

- sequential number

- Year

- Antigen formula (H or N)

Example: Influenza A/ California/7/2009(H1N1)

Influenza A and Influenza B are spread worldwide, while Influenza C occurs only sporadically.

Route of transmission: Transmission occurs by droplet infection and also by smear infection. However, there must be a high virus titre in the nasopharyngeal secretion.

Obligation to report: According to § 7 of the Infection Protection Act (IfSG), there is a nationwide obligation to report influenza viruses by name in the laboratory if they are directly detected.

In Saxony, according to the Ordinance on the extension of the obligation to report communicable diseases and pathogens under the Infection Protection Act § 1, there is also an obligation for the doctor to report both the disease and death from influenza by name.

Important: After an influenza vaccination, the HIV test can be false positive for up to 3 weeks!

1. Herold et al. (2017) Internal Medicine p 875-877
2. Infection Protection Act (IfSG) of the Federal Ministry § 7 Reportable evidence of pathogens.
3. Köhler et al. (2010) Pneumology 54: 90
4. Li YT et al. (2019) Avian influenza viruses in humans: lessons from past outbreaks. Br Med Bull 132: 81-95.
5. Loscalzo J et al (2011) Harrison's pulmonary medicine and intensive care p 163-175.
6. LVWA Saxony Additional reporting obligation according to the ordinance on the extended reporting obligation for communicable diseases.