RESUMO
BACKGROUND: The human papillomavirus (HPV) vaccine is recommended for male and female recipients aged 9-26 years, and is effective in preventing HPV infection and cancer precursors. However, there is variability in immunogenicity among recipients as measured by anti-HPV geometric mean titers. In this study, we explored the effect of stress level on the immunogenicity of the HPV vaccine among college age males. METHODS: 220 males aged 18-25 y were randomly assigned to 6-month (0, 2, and 6) and 12-month (0, 2, and 12) dosing schedules. Antibody titers were measured before the first dose and 2-6 weeks following the final dose. We recorded participants' age and stress level, based on a 4-item Perceived Stress Scale (PSS-4) questionnaire. RESULTS: The average age of participants was 21.3 y old. Inspection of titers by quartile on the stress scale generally showed highest titers with highest stress. Spearman correlation coefficients revealed significant correlation between stress and titers for HPV-6, 16, and 18 but not for HPV-16 in the group of 6-month dosing schedule; no associations were found for the 12-month dosing schedule. For most strains, linear regression revealed significant (P > 0.05) associations on antibody titer for categorical age and dosing schedule but not stress. CONCLUSION: The evidence is mixed for an association between stress and HPV vaccine response for the 6-month dosing schedule, but no association was found for stress for the 12-month dosing schedule. Further investigations with larger and more diverse population groups are needed to explore the association between stress level and vaccine immunogenicity.
