Giving the HPV vaccine to teenage girls does not encourage them to engage in risky sexual behavior. Researchers at Massachusetts General Hospital were curious as to why only 38 percent of young Americans have been vaccinated against the human papillomavirus, compared with 80 percent of eligible Australians. Their findings were published today in the Journal of the American Medical Association.

The reason for the under performance of the vaccine is thought to be that parents and physicians are hesitant to inoculate young girls against the sexually transmitted HPV disease for fear that it will encourage the girls to have unprotected sex.

“I’d like to emphasize that it’s a real concern. It’s not something to automatically dismiss but that’s why we need some scientific evidence to show we’re on the right path,” said Dr. Anupam Jena, lead author of the study and an assistant professor at Harvard Medical School.

The stated objective of the study was to see “whether HPV vaccination of females is associated with increases in STI rates.” To do this, researchers compared the insurance records of 21,610 vaccinated girls, before and after they received the injections, with the records of 186,501 girls who were not vaccinated. The comparison found that the rates of infections, such as chlamydia, gonorrhea, herpes, etc., rose at the same rates for both groups. This means that getting the HPV vaccine did not promote excessively reckless sexual behavior in teenage girls.

“This is probably the most definitive evidence yet that vaccinating your child against HPV is unlikely to lead them to be more sexually active, at least in an unsafe way,” said Dr. Jena.

HPV is the most common sexually transmitted disease in the United States. Nearly 80 percent of men and women will be infected with one of the 40 strains of HPV at some point in their lives. The body can fight off some of the strains of the virus by itself. Other strains cause genital warts. The worst strains, and the ones the vaccine hopes to guard against, cause cervical cancer if left untreated. Cervical cancer is fourth deadliest cancer among women throughout the world.