The HPV vaccine, which can help prevent cervical cancer, is most effective when given to girls before they become sexually active. But advocates of abstinence-only education have argued that the vaccine will convince teens it's okay to have sex; Christian author Teresa Tomeo, for instance, wrote, "We don't pass out filtered cigarettes or light beer to our youth. Why would we give them more reason to engage in unsafe behavior?" Now a UK study has found that the vaccine doesn't make girls more likely to have sex, or significantly less likely to use protection if they do.
Behavioral health researcher Alice Forster and her coauthors surveyed over 1,000 UK teenagers, some of whom had received the HPV vaccine and some of whom had not. They compared the sexual activity of one group of girls who had been offered the vaccine to another group who hadn't. And they followed two more groups of girls over several months, one that had been vaccinated and one that hadn't, to see if the vaccine changed their sexual behavior.
The study authors found that girls who had been offered the vaccine were actually slightly less likely to be sexually active than girls who had not — 41.2% of girls who had been offered the vaccine had had sex, compared to 41.6% of girls who hadn't. This difference, though, was so small as to be statistically insignificant.
Among the girls they followed for several months, those who were vaccinated were more likely to be sexually active, and more likely to be inconsistent with condoms, than those who weren't. But the girls who ended up getting vaccinated had already been more sexually active, and less likely to use condoms, before they ever got the vaccine (Forster et al write that girls who were sexually active when they were offered the vaccine may have been more likely to accept it). When the study authors looked at changes in sexual behavior among vaccinated and unvaccinated girls, they found no differences — the vaccine didn't make the girls significantly more likely to have sex or be lax about condoms.
Forster's study bolsters the conclusions of a CDC study last year, which also found that the HPV vaccine didn't change girls' sexual behavior. And it counters a study this January that found that some girls erroneously believed the HPV vaccine could protect them against other STDs (even in that study, a large majority believed safer sex practices like condoms were still necessary). Perhaps most importantly, it shows that getting vaccinated against HPV doesn't make teen girls go out and have sex, unprotected or otherwise.