The influenza virus has three types: A, B and C. A and B viruses are constantly mutating, so health authorities at each epidemiological season predict a probable genetic makeup of the virus and preparing vaccines and serums on the basis of these forecasts.
Immunologists have conditionally divided influenza subtypes into two groups: the first includes the H1, H2 and H5, and the second - H3 and H7. When a person first becomes infected with influenza virus, the biological defense system in fighting pose "protect" it from a given subtype. In the future, the body will not be susceptible to the this kind of virus, but would be susceptible to other types.
For many years, twice a year, the WHO recommendates a vaccine composition aimed for three (trivalent) most common types of virus circulating in the population (two subtypes A and one subtype B). From 2013-2014 years in the northern hemisphere it is recommended quadrivalent vaccine with a second virus B.
According to WHO recommendations, all influenza vaccines 2016/2017 season contain the following strains of influenza virus types A and B:
The presence of human biological defense system against a particular virus is dependent on his age. Subtype H5N1 circulated until 1960, after - the H7. Accordingly, the biological defense systems were prepared the antibodies on these strains and was defenseless to other mutations. Until 2007, the vaccine strains match the epidemic strains. In the season of 2007/2008. and later this line was smaller.
Given the global nature of the spread of influenza, its prevention is noteworthy. Annual diagnostics, hospitalization of children and adults cause economic losses of billions of rubles. Adults take leave to care for children, or come to the hospital themselves, children miss school. Reducing the incidence of the most common diseases - both economically and socially important area of clinical research.
Center for Control and Prevention of diseases in two clinical trials confirmed the reduction in mortality and complications after influenza vaccination. Antibodies produced by the biological defense system in response to vaccination with one strain can protect against related strains.
Every year in Russia in the epidemiological season 20-25% of the population are vaccinated. biological protection systems form immunity from day 14 and for the entire season. Since 2006, influenza vaccination is included in the National calendar of preventive vaccination of the Russian Federation. According to Federal Law №157 "About immunoprophylaxis of communicable diseases" Annual influenza vaccination to be:
At SanPin 3.1.2.1319-03 "Preventing flu" vaccination of risk groups is recommended also to:
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