Why is antigenic drift a problem for the immune system?

Question

Quizplus · Accepted Answer

Antigenic drift refers to the gradual accumulation of mutations in the genes encoding viral surface proteins, leading to changes in the antigenic epitopes presented to the immune system. This means that the immune system may not be able to recognize the altered antigen, and a new, primary response by B cells may be required. Additionally, T cell receptors may not be able to recognize the altered antigen, further compromising the immune response. Therefore, antigenic drift is a problem for the immune system as it may require a new, primary response by both B and T cells, and the altered antigen may not be recognized by the immune system.

Why Is Antigenic Drift a Problem for the Immune System