Many people are concerned human papillomavirus (HPV) vaccination may promote unsafe sexual activity, but a new study of adolescent girls finds that HPV vaccination was not associated with increases in sexually transmitted infections (STIs).

Nearly one-quarter of U.S. females between the ages 14 and 19 and 45 percent of women between the ages of 20 and 24 are affected by HPV. The HPV vaccination can prevent cervical, vulvar and vaginal cancers and genital warts caused by certain HPV strains. Still, HPV vaccination rates remain low in the United States and, by 2013, only 57 percent of females between the ages of 13 and 17 had received at least one dose, whereas only 38 percent had received all three recommended doses, according to the study background.

Researchers at Harvard Medical School found that the use of the vaccination increased over time with 27.3 percent of females receiving the vaccination by the end of 2010 compared with just 2.5 percent of females at the end of 2006. The study included 21,610 females who were vaccinated against HPV and 186,501 matched females who were nonvaccinated.

For the study, researchers analyzed a large insurance database of females ages 12 to 18 from 2005 to 2010 to examine STIs among girls who were not vaccinated and those who were not.

They found that females who were vaccinated were more likely to be sexually active in the year before vaccination compared with those who were nonvaccinated. Study results also indicate that vaccinated females had higher rates of STIs before and after vaccination compared with those who were nonvaccinated.

"We found no evidence that HPV vaccination leads to higher rates of STIs. Given low rates of HPV vaccination among adolescent females in the United States, our findings should be reassuring to physicians, parents and policy makers that HPV vaccination is unlikely to promote unsafe sexual activity," the study concludes.

The findings are detailed in the journal JAMA Internal Medicine.