(RxWiki News) Only one vaccine currently protects against an infection that can directly cause cancer — the HPV vaccine. Good news about that vaccine is that research is showing that it's working very well.
A recent study showed that HPV infections of the strains in the vaccine were cut in half among teen girls.
Preteens and teenagers are the group recommended to get the vaccine because it is most effective before a person becomes sexually active.
HPV stands for human papillomavirus, a sexually transmitted infection that can cause cancer in the cervix, throat and neck, penis and anus.
"Ask your doctor about the HPV vaccine."
The four strains they looked at were HPV-6, HPV-11, HPV-16 and HPV-18. These are the four strains the HPV vaccine protects against.
The researchers looked at how many women, aged 14 to 59, among a sample of 4,150 had those HPV strains from 2003 to 2006, before the vaccine became available in late 2006.
Then they compared these numbers to the how many women among a sample of 4,253 had those HPV strains in 2007 to 2010, after the vaccine had been introduced.
When it was introduced, the vaccine was recommended for 11- and 12-year-olds and, in a catch-up schedule, for those aged 13 to 26.
By 2010, about a third (32 percent) of teens aged 13 to 17 had received all three doses of the vaccine.
The researchers found that half as many teenagers had those HPV strains after the vaccine had been introduced than before it was available.
Among girls aged 14 to 19, a total of 5.1 percent had HPV in 2007-2010, compared to 11.5 percent of girls in that age group from 2003-2006. That reduction is a 56 percent reduction in just a few years.
The researchers did not find any changes in how many women had those HPV strains in other age groups. That finding makes it clear that the reduction in HPV for teen girls can be attributed to the vaccine, the researchers noted.
Having at least one dose of the vaccine is estimated to be 82 percent effective at preventing those four strains of HPV.
Those four strains of HPV are the ones responsible for the vast majority of cancers caused by HPV, including cervical cancer, neck and throat cancers and penile or anal cancer.
The vaccine is currently recommended by the Centers for Disease Control and Prevention (CDC) for both preteen girls and boys.
This study was published June 19 in The Journal of Infectious Diseases.
The research was funded by the Division of STD Prevention at the National Center for HIV, Viral Hepatitis, STD and TB Prevention and by the National Center for Health Statistics at the CDC. The authors declared no conflicts of interest.