Flu Vaccines Work

Close-up of multiple vaccine vials
Flu vaccine effectiveness is influenced by a variety of different factors.
VE estimates vary across studies due to differences in design, outcome(s), and population studied.
CDC and ACIP recommend annual flu vaccination for all people 6 months and older.

Resources

How Flu Vaccine Effectiveness and Efficacy are Measured
Randomized controlled trials and observational studies assess how well flu vaccines work.
Many more people could be protected from flu if more people got vaccinated.