(RxWiki News) One of the concerns expressed by some parents about the HPV vaccine is that getting it might encourage their daughters to have sex sooner. Not so, says a new study.
A recent study has found girls receiving the HPV vaccine did not increase their sexual activity more than unvaccinated girls.
HPV stands for human papillomavirus. It's a sexually transmitted infection that can cause genital warts, cervical cancer and other cancers.
"Vaccinate your child against HPV."
The study, led by Robert A. Bednarczyk, PhD, of the Center for Health Research-Southeast at Kaiser Permanente in Atlanta and from the Rollins School of Public Health, focused on whether girls who got the HPV shot became more sexually active afterward.
The study drew from data on 1,398 girls, aged 11 and 12, who were enrolled in a managed care organization between July 2006 and December 2007.
A total of 493 of these girls received the HPV vaccine along with other routine immunizations recommended by the Centers for Disease Control and Prevention. The other 905 girls did not receive the HPV vaccine.
They were then tracked for about three years, up through December 2010, to see if they became pregnant, came in for sexually transmitted infection (STI) testing, were diagnosed with an STI or received contraceptive counseling during that time.
These findings were then adjusted to take into account typical healthcare behavior for girls with similar demographics.
The researchers found that girls receiving the vaccine were no more likely to become pregnant, seek STI testing, get an STI diagnosis or receive counseling on contraception than girls who did not receive the vaccine.
There were no meaningful differences in the number of girls who became pregnant or who got a chlamydia infection, regardless of whether they were given the HPV vaccine or not.
The authors therefore concluded that the HPV vaccination "was not associated with increased sexual activity-related outcome rates."
The researchers chose to measure likelihood of increased sexual activity using pregnancy and STI information because self-reporting of sexual activity by teens is not always accurate. Teens may overestimate or underestimate their actual sexual activity.
The HPV vaccine is recommended by the CDC for girls and boys at age 11 and 12. These ages were selected because they were estimated to be before the majority of preteens become sexually active which then puts them at risk for contracting HPV.
Women are advised to get the vaccine up until they are age 26 if they did not get it at an earlier age. Men are advised to get it up through age 21.
The HPV vaccine does not protect against all forms of the STI, but it does protect against four strains that cause the majority of genital warts and the lesions that lead to cervical cancer.
Boys are encouraged to get the shot because they can be carriers of the virus that they pass on to sexual partners and because some HPV strains are also linked to cancer of the penis, anus, mouth and neck.
The study was published October 15 in the journal Pediatrics. The research did not receive external funding. One author served as Chair of the Data and Safety Monitoring Board for the study “A Post Licensure Surveillance Program for the Safety of Gardasil in a Managed Care Setting,” which was funded by Merck Pharmaceuticals, Inc.
Another author conducted HPV vaccine clinical trials with funding from Merck, Roche and the National Institute of Allergy and Infectious Diseases. An award provided to a third author came from a National Foundation of Infectious Diseases grant funded by Merck, though the author had no direct contact with Merck.