The Effect of Prevaccination Analgesics on Influenza Vaccine Immunogenicity and Effectiveness

Analgesic medications are sometimes taken prior to vaccination to prevent local and systemic adverse reactions. Although studies have examined the association between postvaccination analgesic use and immunogenicity, few have evaluated the effects of prevaccination analgesic use. This analysis assessed antibody response, influenza-like illness (ILI), and influenza infection among adults with and without analgesic use before influenza vaccination.

The Pragmatic Assessment of Influenza Vaccine Effectiveness in the DoD (PAIVED) study was an open-label, randomized trial evaluating the effectiveness of FDA-licensed influenza vaccines during 4 influenza seasons in adult military healthcare beneficiaries. PAIVED participants with data on analgesic use within 24 hours before vaccination were included in this analysis if they either provided prevaccination and postvaccination venous blood samples or participated in weekly ILI surveillance.

Among 684 PAIVED participants with prevaccination and postvaccination antibody titers, 10.4% (n = 71) reported analgesic use before influenza vaccination. Multivariable analyses showed no association between analgesic use and geometric mean titer fold change. There was a modest association between acetaminophen use and increased seroconversion to influenza A/H3N2 compared with no analgesic use (aIRR = 1.37; P = .022); however, this association was not significant in sensitivity analyses adjusting for multiple comparisons. Among 10 723 PAIVED participants with ILI surveillance data, 10.6% (n = 1140) reported prevaccination analgesic use. Multivariable analyses revealed no association between analgesic use and incidence of ILI or odds of influenza infection.

These findings suggest acetaminophen and/or nonsteroidal anti-inflammatory analgesic use within 24 hours before influenza vaccination does not reduce vaccine immunogenicity or effectiveness in adults.