A study out of New Mexico finds that the vaccine against human papillomavirus (HPV) infection, which doctors believe causes most cases of cervical cancer, could be much more effective than previously thought.
"After eight years of vaccination, the reduction in the incidence of cervical neoplasia [abnormal growth of cells], including pre-cancers, have been reduced approximately 50 percent. This is greater than what was expected -- that's pretty exciting," said lead researcher Cosette Wheeler. She is a professor of pathology and obstetrics and gynecology at the University of New Mexico, in Albuquerque.
Researchers also found that one or two doses of the vaccine may provide as much protection as the recommended three.
"Right now, the recommendation is three doses for girls and boys before the 13th birthday, so that you are protected before you become exposed," Wheeler explained.
"People thought that three doses of vaccine were necessary, but there's a lot of people who are getting one and two doses, and people are getting protection from one or two doses," she said.
Another benefit is that the vaccines protect against more types of HPV than they were designed to do, noted Wheeler.
Other studies have pointed to the effectiveness of the vaccine, but this is the first study to show declines in precancerous lesions across a large population.
This study even took into account changes in Pap test screening over the last 10 years.
In 2009, the American College of Obstetrics and Gynecology said most women under 21 do not need Pap test screening and recommended longer times between screening. In 2012, the U.S. Preventive Services Task Force said women, regardless of age, do not need to get screened more than every three years, Wheeler said.
If these changes were not taken into account, the effect of the vaccine would appear even greater than it already is, because it would assume that more women were being screened than actually were, she said.
"Parents and doctors should pay attention. These vaccines are highly efficacious," Wheeler said.
Cervical cancer can take decades to develop so it’s important to protect children before they become sexually active.
The Centers for Disease Control and Prevention (CDC) recommends that the HPV vaccine be given to vaccine is preteen boys and girls at age 11 or 12 so they are protected before ever being exposed to the virus. The HPV vaccine also produces a more robust immune response during the preteen years. Finally, older teens are less likely to get heath check-ups than preteens. If your teen hasn't gotten the vaccine yet, talk to their doctor or nurse about getting it for them as soon as possible.
For the study, Wheeler and colleagues collected data on young women tested for cervical cancer with Pap tests from 2007 to 2014, who were part of the New Mexico HPV Pap Registry. New Mexico should be considered representative of the whole country, Wheeler said.
One expert said the findings make the case for HPV vaccination even stronger.
"These data highlight and provide even more evidence as to the efficacy of the vaccine in preventing HPV infections and related diseases," said Fred Wyand, a spokesman for the American Sexual Health Association/National Cervical Cancer Coalition.
Wyand suggests that one way to increase HPV vaccination rates is for health providers to stress the importance of the vaccine to parents.
Another way is to “normalize” the vaccine.
"Rather than treat it as something exotic, it should just be offered as part of the routine adolescent vaccine program," Wyand said.
The report was published online Sept. 29 in the journal JAMA Oncology.
Story sources: Steven Reinberg, http://www.webmd.com/sexual-conditions/hpv-genital-warts/news/20160929/hpv-vaccine-more-effective-than-thought-study#1