Doctors recommend people with weak immune systems to get the flu vaccine every year because viruses mutate and their bodies already have a resistance.
Flu is common viral infection caused by a virus and attacks the lungs, nose and throat.
Vaccine for flu infections helps the immune to recognize and attack antigens from the flu virus.
Virus are known to mutate. Because of this, a weak immune system might not recognize the new mode of the virus which multiplies and cause damage to the system.
Therefore, old people and those with weak immune system are always advised to get the vaccine every year because whenever new variant are discovered, vaccine are improved and help the weak immune to recognized and attack any variant of the flu virus.
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