People do not develop a secondary immune response to influenza because
A) the immune system mutates from season to season.
B) flu vaccines are not always effective.
C) secondary immune responses are only possible against bacteria.
D) the primary immune response is sufficient to protect against flu.
E) the virus mutates, so it is different each season.

Question

Quizplus · Accepted Answer

Influenza viruses are known for their high mutation rates and ability to undergo antigenic drift and shift leading to changes in their surface proteins. As a result, the virus can avoid recognition by the immune system and evade pre-existing antibodies, thus preventing the development of a secondary immune response.

People Do Not Develop a Secondary Immune Response to Influenza