Study debunks fears of flu vaccine side effects

No systemic differences between vaccine, placebo

The findings of a recent study should prove useful to employee health practitioners struggling to run influenza vaccination programs with less than optimal compliance. Investigators at the Veterans’ Affairs Medical Center in Minneapolis found that influenza vaccination of healthy working adults is not associated with higher rates of systemic symptoms when compared with placebo injection.1

U.S. Centers for Disease Control and Prevention recommendations emphasize the need for health care workers to receive annual influenza immunizations to protect themselves and high-risk patients,2 yet an unpublished CDC survey found that in about half of U.S. hospitals, less than 25% of workers are immunized. Reports suggest that fear of side effects is a major reason for avoiding vaccination.3 (See Hospital Employee Health, October 1997, pp. 117-119.)

The double-blind, placebo-controlled, randomized study included 424 subjects who received vaccine and 425 who received placebo. Ages ranged from 18 to 64. Vaccine recipients more often reported arm soreness at the injection site (24% of placebo recipients compared with 64% of vaccine recipients), but it generally lasted less than 48 hours. For both groups, more than 95% of subjects with the symptom indicated that the arm soreness was mild or moderate. Vaccine recipients with arm soreness were no more likely to report decreased use of their arm than were placebo injection recipients. Younger subjects and women who received vaccine were more likely to report arm soreness.

No differences were seen in systemic symptoms experienced seven days after placebo and vaccine injection. Systemic symptoms evaluated included fever, myalgia, fatigue, malaise, and headaches.

In addition, no differences were seen between the two groups in activity levels, overall health, coincidental upper respiratory tract illness, or sick leave during the week after the study injection.


1. Nichol KL, Margolis KL, Lind A, et al. Side effects associated with influenza vaccination in healthy working adults. Arch Int Med 1996; 156:1546-1550.

2. Centers for Disease Control and Prevention. Prevention and control of influenza: Recommendations of the Advisory Committee on Immunization Practices. MMWR 1996; 45(No. RR-5).

3. Nichol KL, Hauge M. Influenza vaccination of healthcare workers. Infect Control Hosp Epidemiol 1997; 18:189-194.