VACCINE IMMUNE-RESPONSE AND SIDE-EFFECTS WITH THE USE OF ACETAMINOPHEN WITH INFLUENZA VACCINE

The purpose of this study was to determine whether acetaminophen impai rs the immune response to influenza vaccine. Influenza vaccine is an u nder-utilized preventive measure, partly because of the unfounded perc eption that fever and myalgias frequently follow vaccination. While ac etaminophen may decrease these infrequent side effects, it may also al ter the immune response to vaccination. We compared the effect of acet aminophen with placebo on the humoral immune response to the 1991-1992 commercially available influenza vaccine. We studied 60 healthy, elde rly subjects from a geriatric clinic and 20 infirm, elderly subjects f rom a nursing home. The subjects were randomly assigned to receive pla cebo or acetaminophen (1,000 mg every 6 h) for 2 days. Acetaminophen d id not depress or enhance the immune development of serum hemagglutina tion inhibition antibody to the three vaccine antigens. The systemic s ide effects of fever and myalgia were uncommon in both groups. The hea lthy elderly subjects mounted a significantly better immune response t o the influenza virus A/Taiwan/1/86 (H1N1) vaccine strain than did the infirm elderly subjects (geometric mean titer, 115 versus 51; P = 0.0 03). The functional activity score obtained by using the chronic healt hy evaluation component of the Acute Physiology and Chronic Health Eva luation system could be used to distinguish the healthy from the infir m elderly (scores of 1.27 versus 3.75, P < 0.001). Acetaminophen neith er depressed nor enhanced the serum antibody response to the vaccine i n the healthy and infirm elderly subjects studied.