Table 1.

Studies that examined the influence of HPV vaccination on pregnancy and STI rates among young females

Smith et al,3 2015Canada6 population-based administrative databasesAge 13–17 y; 128 712 vaccinated and 131 781 unvaccinatedNo evidence that vaccination increased the risk of composite end point: RR = 0.96, 95% CI 0.81 to 1.14
Bednarczyk et al,9 2012United StatesCohort study using medical recordsVaccinated at age 10–12 y; 493 vaccinated and 905 unvaccinatedRisk of composite end point not elevated: IRD = 1.6, 95% CI −0.03 to 2.24, per 100 PY
No difference in pregnancy diagnosis: IRD = 0.07, 95% CI −0.20 to 0.35, per 100 PYNo difference in diagnosis of Chlamydia trachomatis: IRD = 0.06, 95% CI −0.30 to 0.18
Liddon et al,10 2012United StatesData from the National Survey of Family GrowthAge 15–24 y; 279 vaccinated and 964 unvaccinatedNANo difference in receiving STI service in past year among those aged 15–19 y (38.7% [95% CI 27.7% to 51.0%] vs 28.9% [95% CI 23.3% to 35.2%])
Rysavy et al,11 2014United StatesCross-sectional survey, using assisted interviewsAge 13–23 y; 153 vaccinated and 70 unvaccinatedNot being vaccinated was associated with pregnancy (20% vs 9%, P = .016)No difference in the proportion of C trachomatis, gonorrhea, genital herpes, syphilis, pubic lice, HIV, genital warts, HPV, trichomoniasis, and hepatitis B infections between vaccinated and unvaccinated participants
Kumakech et al,12 2017UgandaPopulation-based comparative cross- sectional surveyAge 15–24 y (median age was 18.6 y); 438 females (53% of whom were vaccinated)NANo statistically significant difference between vaccinated and unvaccinated participants regarding the history of STD syndrome and the prevalence of syphilis and HIV infections
Jena et al,13 2015United StatesInsurance claim databaseAge 12–18 y; 21 610 vaccinated and 186 501 unvaccinatedNAHPV vaccination was not associated with an increase in STIs: OR = 1.05, 95% CI 0.80 to 1.35
Cummings et al,14 2012United StatesComparison of a group of vaccinated adolescent girls with historical controls. Questionnaires and clinician- or self- collected vaginal swabsAge 14–17 y; 75 vaccinated and 150 matched unvaccinatedNANo differences in diagnoses for C trachomatis and Trichomonas infections between vaccinated and unvaccinated adolescent girls: OR = 0.9, 95% CI 0.04 to 2.20, and OR = 5.3, 95% CI 0.7 to 42.3, respectively
Sadler et al,15 2015United KingdomClinical histories from genitourinary medicine clinic visitorsAge 14–20 y; 231 vaccinated and 132 unvaccinatedNANot being vaccinated was positively associated with receiving C trachomatis diagnosis: OR = 2.30, 95% CI 1.06 to 5.00
  • HPV—human papillomavirus, IRD—incidence rate difference, NA—not applicable, OR—odds ratio, PY—person-years, RR—relative risk, STD—sexually transmitted disease, STI—sexually transmitted infection.

  • * Only studies including some participants younger than 18 years of age were included in this table. Studies including only adults were not included in this review.