An individual receives a flu vaccine and is well protected for the current flu season. The following flu season, the individual fails to get another flu vaccine and comes down with the flu. What is the most likely explanation for vaccine ineffectiveness in the subsequent flu season?

Question

Quizplus · Accepted Answer

The flu virus mutates rapidly, allowing it to evade detection by the immune system. This means that even if an individual receives a flu vaccine one year, they may not be protected against the flu the following year if the virus has mutated into a new strain that is not covered by the previous vaccine. This is why a new flu vaccine is developed every year to try and provide protection against the most current strains of the virus.

An Individual Receives a Flu Vaccine and Is Well Protected