Propose an explanation for why we need a flu shot year after year, instead of only once early in life.

Verified step by step guidance

1. Understand the nature of the influenza virus: The influenza virus is highly mutable, meaning it changes its genetic makeup frequently. This results in different strains of the virus circulating each year.
2. Recognize the concept of antigenic drift: Antigenic drift refers to the small genetic changes that occur in the influenza virus over time. These changes can alter the surface proteins of the virus, specifically hemagglutinin and neuraminidase, which are the primary targets of the immune response.
3. Acknowledge the immune system's response: When you receive a flu shot, your immune system produces antibodies to fight the specific strains of the virus contained in the vaccine. However, due to antigenic drift, these antibodies may not recognize new strains that appear in subsequent years.
4. Consider the role of annual vaccination: Each year, the World Health Organization (WHO) and other health agencies analyze data to predict which influenza strains are most likely to circulate in the upcoming flu season. The annual flu vaccine is then formulated to target those specific strains.
5. Realize the importance of yearly vaccination: Getting a flu shot every year is crucial because it updates your immune system to protect against the most current and common circulating strains of the influenza virus, maximizing your defense against the flu.