HPV rates have fallen dramatically in teenage girls since the introduction of the HPV vaccine in 2006, according to a new study by the Centers for Disease Control and Prevention. In fact, the rates have fallen by over half – 56%, to be precise – for the four different strains of HPV covered by the vaccine, including HPV 6, HPV 11, HPV 16 and HPV 18.
None of the researchers expected such a large drop so quickly, especially since only roughly 33% of teen girls received at least one HPV vaccine dose between 2007 and 2010. In order for the vaccine to be fully effective, it must be applied three times over the course of half a year. The vaccine, along with prevention techniques such as sexual partner limiting and condom use could prove to be highly effective methods for ensuring that teenagers avoid contracting the disease.
HPV Causes Cancer
HPV, or the human papillomavirus, causes about 8,000 cases of throat cancer in men and 19,000 cases of cervical cancer in women every year. HPV 16 and HPV 18, the two strains of the virus believed to cause over 70% of HPV-related cervical cancer cases, are among the strains included in the vaccine. However, other, more atypical strains of HPV are not currently included in the vaccine.
The full study actually included not just teens, but women from 14 up to 59 years old. In order to conduct their study, CDC researchers tested 4,150 women from 2003 to 2006 and another 4,253 women from 2007 to 2010. In the 14 to 19 age group, about 11.5% of girls tested positive for HPV between 2003 and 2006. Among the same age group tested in 2007 through 2010, only 5.1% of girls tested positive for one of the HPV strains covered by the vaccine. Interestingly, HPV rates stayed the same among other age groups.
When Should People Receive the HPV Vaccine?
According to the CDC, children should receive the HPV vaccine when they’re either 11 of 12 years old. The primary goal is to ensure vaccination before any sexual activity occurred, since HPV is sexually transmitted. People who were not vaccinated in their teens are advised to get vaccinated before they reach the age of 26.
But the question remains – how did the rate among teenage girls drop by more than half when no more than a third of teen girls were vaccinated? According to the CDC researchers, the answer lies in the fact that once a large segment of the population is vaccinated, even unvaccinated people will be less likely to contract the virus because there are less people carrying it as well. Although it’s possible that the decline was due in part to a reduction in sexual behavior among teens, the CDC found no direct evidence of this.
According to CDC director Dr. Tom Frieden, the study is a strong indication that the HPV vaccine is very effective. Frieden hopes that people will take the news as encouragement to have their children vaccinated.
The Bottom Line
A new report from the CDC indicates that HPV rates among teenage girls have plummeted by more than half since the HPV vaccine was introduced. The full text of the study can be found in the Journal of Infectious Diseases.