There are 3 main types of influenza viruses; A, B and C. Influenza A viruses are able to infect to both animals and human while B and C viruses are found in only human. A viruses are the severest type then B and C viruses in order however, only A viruses cause pandemic.
Influenza A derived from a combination of 2 proteins on surface of flu viruses: the hemagglutinin (H), and the neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes and furthermore A viruses can be broken down into different strains as well. The example of A virus is H1N1 merged from hemagglutinin 1 with neuraminidase1. This subtype was outbreak in 2009. Influenza B viruses is not similar to A viruses, this type is not divided into subtypes but still broken down into different strains.
Currently, influenza A and B are already included in influenza vaccines updated additional every year nevertheless, due to subtypes and strains of influenza viruses can constantly change and mutate all the time and always replace the older strains of virus. This means that influenza vaccine cannot protect human against influenza C or any new subtypes or strains.
There are 3 main types of influenza viruses; A, B and C. Influenza A viruses are able to infect to both animals and human while B and C viruses are found in only human. A viruses are the severest type then B and C viruses in order however, only A viruses cause pandemic.
Influenza A derived from a combination of 2 proteins on surface of flu viruses: the hemagglutinin (H), and the neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes and furthermore A viruses can be broken down into different strains as well. The example of A virus is H1N1 merged from hemagglutinin 1 with neuraminidase1. This subtype was outbreak in 2009. Influenza B viruses is not similar to A viruses, this type is not divided into subtypes but still broken down into different strains.
Currently, influenza A and B are already included in influenza vaccines updated additional every year nevertheless, due to subtypes and strains of influenza viruses can constantly change and mutate all the time and always replace the older strains of virus. This means that influenza vaccine cannot protect human against influenza C or any new subtypes or strains.
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