Does the HPV vaccine encourage teens to have sex?
Here is what the checked sources say. Each title links to the original.
Effect of human papillomavirus (HPV) vaccination on clinical indicators of sexual behaviour among adolescent girls: the Ontario Grade 8 HPV Vaccine Cohort Study
Compared 260,493 Ontario girls in grade 8 just before and just after the province started offering HPV vaccine at school, then tracked two clinical indicators of sexual behavior, pregnancy and non-HPV sexually transmitted infections, in grades 10 to 12. The study found no evidence that vaccination increased these outcomes (relative risk 0.96, 95% CI 0.81 to 1.14), and no effect of program eligibility. Behavior itself was not measured directly. The authors wrote that the results suggest concerns about increased promiscuity after HPV vaccination are unwarranted.
Sexual activity-related outcomes after human papillomavirus vaccination of 11- to 12-year-olds
Followed 1,398 girls vaccinated at age 11 or 12 in a large US health plan (493 received HPV vaccine, 905 did not) for up to 3 years. A combined clinical marker of sexual activity (pregnancy or sexually transmitted infection testing or diagnosis, or contraceptive counseling) was not significantly higher in girls who got the HPV vaccine (adjusted rate ratio 1.29, 95% CI 0.92 to 1.80). The authors concluded HPV vaccination at the recommended ages was not associated with increased sexual activity-related outcome rates.
Human Papillomavirus Vaccination and Sexual Disinhibition in Females: A Systematic Review
Pooled 21 studies from 12 countries with 527,475 girls and women aged 11 to 40, measuring age at first sex, risky sex, condom and contraception use, sexually transmitted infections and pregnancy. Studies found either no association between HPV vaccination and these outcomes or an association with safer behavior such as condom use. All but one study were of moderate or weak quality. The review concluded there was not sufficient evidence of riskier sexual behavior after vaccination.
Human Papillomavirus: The Disease & Vaccine
A parent-friendly page explaining that studies, including one of more than 260,000 Ontario girls, found no increase in sexual-activity indicators such as pregnancy and non-HPV sexually transmitted infections after HPV vaccination. It recommends vaccinating before sexual activity starts because HPV infections are common in young people, not because behavior is expected to change, and reminds families the vaccine does not protect against other sexually transmitted diseases.