SIDE-EFFECTS ASSOCIATED WITH INFLUENZA VACCINATION IN HEALTHY WORKINGADULTS - A RANDOMIZED, PLACEBO-CONTROLLED TRIAL

Background: Concern about side effects is a barrier to influenza vacci nation. This randomized, double-blind, placebo-controlled trial assess ed side effects following vaccination among healthy working adults. Me thods: Healthy working adults were recruited during October and Novemb er 1994 and were randomized to receive influenza vaccine or placebo in jections. Local and systemic symptoms during the week following the in jection were evaluated through structured telephone interviews. Result s: Of 849 subjects enrolled in the study, 425 received a placebo and 4 24 received influenza vaccine. Baseline characteristics were similar b etween the groups, and 99% of subjects completed interviews to assess side effects after the study injection. No differences were seen betwe en the 2 groups for the systemic symptoms of fever, myalgias, fatigue, malaise, or headaches. Overall, 35.2% of placebo and 34.1% of vaccine recipients reported at least 1 of these systemic symptoms (P=.78, chi (2)) Vaccine recipients reported a higher rate of arm soreness at the injection site than did placebo recipients (63.8% vs 24.1%, P<.001). l ocal reactions were mild in both groups and infrequently resulted in d ecreased use of the arm. After logistic regression, female sex (odds r atio [OR], 1.5; 95% confidence interval [CI], 1.1-2.1), age younger th an 40 years (OR, 1.6; 95% CI, 1.2-2.2), and coincidental upper respira tory tract illness (OR, 4.6; 95% CI, 3.2-6.6) were independently assoc iated with higher rates of systemic symptoms. In the multivariate mode l, vaccine again was not associated with systemic symptoms (OR, 0.9; 9 5% CI, 0.7-1.2). Conclusions: Influenza vaccination of healthy working adults is not associated with higher rates of systemic symptoms when compared with placebo injection. These findings should be useful to ph ysicians and other health care providers as they counsel patients to t ake advantage of an important opportunity for disease prevention and h ealth protection.