Why Can't We Make A Better Flu Vaccine?
For several reasons, influenza is arguably humankind’s most heinous and most burdensome infection. First, the virus kills more people than all other vaccine-preventable diseases combined; as many as 50,000 people succumb to influenza in the United States every year. Second, influenza virus mutates so much from one year to the next that preventing it requires a yearly vaccine; neither immunization nor natural infection the previous year protects against disease the following year. Third, because the Centers for Disease Control and Prevention (CDC) recommends the influenza vaccine for everyone more than 6 months of age, the health system is burdened with immunizing hundreds of millions of people every year. Finally, although the influenza vaccine is the best tool available to prevent the disease, it’s less effective than any other vaccine. Last year’s influenza vaccine is a perfect example.
Source: Daily Beast