The rate of infection with the human papillomavirus (HPV) has decreased significantly among teenagers since a vaccine against the virus was introduced in 2006. CNN reports on how the decrease in infection rates has surpassed researchers' expectations and hopes:
"The prevalence of the types of HPV that commonly cause cervical cancer in women has dropped by about half in girls ages 14 to 19," said Dr. Thomas Frieden, CDC director. "That decline is even better than we had hoped for."
Specifically, rates of HPV types 6, 11, 16 and 18 – the four types covered by the vaccines – have decreased by 56% in young girls.
Those numbers are surprising, said Frieden, because only about a third of girls have gotten all three recommended doses of the vaccine. He suggested that the extra immunity may come from girls who only got one or two doses, or so-called "herd immunity." That occurs when those who have been vaccinated cause there to be less virus floating around, therefore lowering the risk for those who haven't been vaccinated.
But despite the good news, Frieden says the CDC had hoped that 80% of girls would be vaccinated by this point, and more needs to be done.
"This should be a wake-up call that we need to increase vaccination rates, because we can protect the next generation of girls from cancer caused by HPV," said Frieden. "Fifty thousand women alive today will develop cervical cancer that could have been prevented if we had reached our goal of an 80% vaccination rate."
In March, an article in the journal Pediatrics called on more parents to vaccinate their children, expressing concern that the overwhelming majority of girls had not received the full course of the HPV vaccine. Another study, published late last year, found that receiving the HPV vaccine does not affect teens' sexual behaviors, a concern for many parents.
Image: Teen getting a shot, via Shutterstock