Sexual Activity–Related Outcomes After Human Papillomavirus Vaccination of 11- to 12-Year-Olds

OBJECTIVE: Previous surveys on hypothesized sexual activity changes after human papillomavirus (HPV) vaccination may be subject to selfresponse biases. To date, no studies measured clinical markers of sexual activity after HPV vaccination. This study evaluated sexual activity–related clinical outcomes after adolescent vaccination. METHODS: We conducted a retrospective cohort study utilizing longitudinal electronic data from a large managed care organization. Girls enrolled in the managed care organization, aged 11 through 12 years between July 2006 and December 2007, were classified by adolescent vaccine (HPV; tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis, adsorbed; quadrivalent meningococcal conjugate) receipt. Outcomes (pregnancy/sexually transmitted infection testing or diagnosis; contraceptive counseling) were assessed through December 31, 2010, providing up to 3 years of follow-up. Incidence rate ratios comparing vaccination categories were estimated with multivariate Poisson regression, adjusting for health care–seeking behavior and demographic characteristics. RESULTS: The cohort included 1398 girls (493 HPV vaccine–exposed; 905 HPV vaccine–unexposed). Risk of the composite outcome (any pregnancy/sexually transmitted infection testing or diagnosis or contraceptive counseling) was not significantly elevated in HPV vaccine– exposed girls relative to HPV vaccine–unexposed girls (adjusted incidence rate ratio: 1.29, 95% confidence interval [CI]: 0.92 to1.80; incidence rate difference: 1.6/100 person-years; 95% CI: 20.03 to 3.24). Incidence rate difference for Chlamydia infection (0.06/100 person-years [95% CI: 20.30 to 0.18]) and pregnancy diagnoses (0.07/100 person-years [95% CI: 20.20 to 0.35]), indicating little clinically meaningful absolute risk differences. CONCLUSIONS: HPV vaccination in the recommended ages was not associated with increased sexual activity–related outcome rates. Pediatrics 2012;130:798–805 AUTHORS: Robert A. Bednarczyk, PhD,ab Robert Davis, MD, MPH,a Kevin Ault, MD,c Walter Orenstein, MD,c,d and Saad B. Omer, MBBS, PhD, MPHabcd aCenter for Health Research-Southeast, Kaiser Permanente, Atlanta, Georgia; and bRollins School of Public Health, cSchool of Medicine, and dEmory Vaccine Center, Emory University, Atlanta, Georgia