The main reason doctors suggest getting a flu vaccine each year is that viruses can mutate from year to year. This means that the flu virus can change its genetic makeup, leading to new strains that may not be covered by previous vaccines. By getting vaccinated annually, individuals increase their chances of being protected against the most prevalent and current strains of the flu virus.
Vaccines do not get stronger over time or get absorbed by the body after a year. Vaccines work by stimulating the immune system to produce antibodies that can recognize and fight specific viruses. While the protection provided by a flu vaccine may decrease over time due to waning immunity, it is still important to get vaccinated each year to enhance immunity against the latest strains of the flu virus.
In summary, the key reason for annual flu vaccination is to ensure protection against evolving flu virus strains, as these viruses can mutate and change from year to year.
