What is the primary reason why it is important to get a new influenza (flu) shot every year?

Question

Quizplus · Accepted Answer

Influenza viruses undergo antigenic shift, which is a sudden and significant change in the structure of viral surface proteins. As a result, the immune system may not recognize the new virus, and a previous flu shot may not provide protection. Getting a new flu shot every year helps the immune system respond quickly to these changes and provide protection against the flu viruses that are likely to circulate that year. A, C, and D are incorrect because the immune system is able to make memory B cells against influenza viruses, can recognize multiple viral antigens, and can devote sufficient B cells to combat infections in the same year.

What Is the Primary Reason Why It Is Important to Get