Medical Research: What is the background for this study? What are the main findings?
Dr. Smith: The human papillomavirus (HPV) vaccine protects against types of HPV that cause cervical cancer and anogenital warts. The vaccine first became available in 2006. Since then, it has faced a great deal of controversy surrounding, in part, some of the unanswered questions about the real-world effects of the vaccine, especially on the young girls targeted for immunization. One issue that has received a great deal of public attention has been the concern that HPV vaccination might give girls a false sense of protection against all sexually transmitted infections that might lead them to be more sexually active than they would otherwise. As a result, some parents have been reluctant to have their daughters vaccinated. It is also reason why some religious groups have spoken out against the vaccine. This question is further important from a public health perspective because increases in risky sexual behaviour would inevitably also lead to increases in teen pregnancy and sexually transmitted infections (excluding anogenital warts), which would of course undermine the potential health benefits of the vaccine.
In this study, we directly addressed the question of whether HPV vaccination has led to increases in pregnancy and non-HPV-related sexually transmitted infections (both of which are proxies for risky sexual behaviour) among adolescent girls.
In our study of over 260,000 girls, we did not find any evidence that the HPV vaccine had a negative impact on these outcomes.
Medical Research: What should clinicians and patients take away from your report?
Dr. Smith: The results of our study provide strong evidence that HPV vaccination does not have an impact on sexual behaviour. Clinicians can use these findings to help reassure the public and parents that girls do not become more sexually active because they have received the HPV vaccine, and that fear of increased sexual behaviour following HPV vaccination should not be a reason why parents decide not to have their daughters vaccinated.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Smith: The vaccine is now also recommended for use in males, but this issue has not yet been studied in this group. Future studies should look at whether the HPV vaccine is associated with an increase in risky sexual activity among boys.