The prevalence of human papillomavirus (HPV) infection in teenage girls has seen a dramatic decrease since the introduction of the HPV vaccine in 2006, according to a new study. The research, published online Feb. 22 in the journal Pediatrics, found the virus rate was decreased by nearly two-thirds in teenage girls and one-third in young adult women.
“We’re seeing the impact of the vaccine as it marches down the line for age groups, and that’s incredibly exciting,” Amy B. Middleman, MD, chief of adolescent medicine at the University of Oklahoma Health Sciences Center, told The New York Times. “A minority of females in this country has been immunized, but we are seeing a public health impact that is quite expansive,” added Middleman, who was not involved in the study.
HPV is among the most commonly sexually transmitted diseases (STDs), and the main cause of cervical cancer. The American Cancer Society estimates 4,120 women will die of cervical cancer this year. HPV can also cause genital warts and anal, penile, and mouth and throat cancers.
Lead study author Lauri Markowitz, MD, a medical epidemiologist at the CDC’s National Center for Immunization and Respiratory Disease, told HealthDay that they “have seen declines in genital warts [caused by HPV] already. The next thing we expect to see is a decline in pre-cancers, then later on declines in cancer.”
For the study, Markowitz and her colleagues used data from the National Health and Nutrition Survey to examine the prevalence of the virus in women and girls of different age groups. The researchers looked at information gathered during the pre-vaccine years of 2003 through 2006 and then at the rates of infection in the same age groups between 2009 and 2012.
Findings showed that during 2009 to 2012, HPV prevalence fell 64 percent, from 11.5 percent to 4.3 percent in girls between the ages of 14 and 19, and by 34 percent, from 18.5 percent to 12.1 percent among women 20 to 24 years of age.
“The vaccine is more effective than we thought,” Debbie Saslow, PhD, a public health expert in HPV vaccination and cervical cancer at the American Cancer Society, told The New York Times. As vaccinated teenagers become more sexually active they’re not spreading the virus, so “they also protect the people who haven’t been vaccinated,” she added.
But it is those who haven’t been vaccinated that are of concern. Despite the effectiveness of the HPV vaccine, only about 40 percent of girls and 20 percent of boys between the ages of 13 and 17 have been vaccinated.
According to the study authors, many parents are reluctant to have their children vaccinated because they see it as being related to sexual activity rather than as a vaccine that can prevent types of cancer. In addition, the researchers found that many primary physicians hesitate to recommend the vaccine because of its association with sexual activity.
What is being overlooked is that the vaccine is most effective in children 11 and 12 when their immune systems are the most robust. Plus, the vaccine provides optimal protection when given before sexual activity begins.
“HPV vaccine needs to be given prior to exposure to these viruses in order to be effective in preventing infections with these viruses, and there is also good immune response to the vaccine early in adolescence,” Ruth Lynfield, MD, a pediatrics researcher and medical director of the Minnesota Health Department, told Reuters by email.
“It’s fine that it is given many years before a person becomes sexually active,” Lynfield added. “It needs to be stressed that it is a cancer prevention vaccine.”
