Do Some Healthy Adults Consistently Have Systemic Reactions to Influenza Vaccines?

Inclusion Criteria:

• Employed or volunteer in a healthcare facility or an ambulatory care setting providing healthcare
• By self report, have had 2 or more doses of trivalent inactivated influenza vaccine (TIIV) in the last 15 years, and after at least the last 2 vaccine doses have had the same systemic adverse event in the 7 days after vaccination, including: fever, chills, myalgia, arthralgia, fatigue, headache, or insomnia;
• Consent to the study, including two injections one month apart, with one being placebo and one a dose of TIIV;

Exclusion Criteria:

• Has a contraindication to TIIV (previous allergic reaction to a dose of vaccine, or Guillain Barre syndrome with onset within 6 weeks of vaccination);
• Has previously received a dose of TIIV for the current influenza season.
• Receipt of another vaccine, or initiation of new medication within 7 days of the study injection (participant may enter the study as long as the gap between other vaccine/initiation of new medication is >7 days);
• Moderate or severe acute illness or active infection or fever (temperature ≥37.8oC) on the day a dose of study medication due (participant may receive injection 48 hours after symptoms have resolved and body temperature has returned to normal without the use of antipyretics.