During previous flu seasons, small variations in the influenza virus resulted in the immune system's inability to fully recognize and respond to flu exposure. As a result, vaccine effectiveness could be as low as 30%. This is an example of __________.

Question

Quizplus · Accepted Answer

Antigenic drift refers to the small changes or mutations in the genes of influenza viruses that happen over time. These changes can lead to differences in the virus's surface proteins, making it harder for the immune system to recognize and fight off the virus, even in vaccinated individuals. This is why flu vaccines need to be updated regularly.

During Previous Flu Seasons, Small Variations in the Influenza Virus