Staying away from sick people is one way to help avoid getting sick, but it’s not foolproof. After all, people can be contagious without showing any symptoms (see Myth #4). Experts point to the flu vaccine as the best preventive measure against the flu. The Advisory Committee on Immunization Practices (ACIP), which advises the CDC on vaccine issues, recommends that all people age 6 months and older receive an annual flu vaccination.