RAY SUAREZ: Now: some striking results affirming a vaccine's effectiveness at reducing infections and a cancer risk.
Margaret Warner has the story.
MARGARET WARNER: Infection by a virus that causes cervical cancer has dropped more than 50 percent in teenage girls since a vaccine against the virus was introduced in 2006. That's the finding in a new study by the Centers for Disease Control and Prevention, testing the effectiveness of the new vaccine against human papilloma virus, or HPV.
It found the infection rate in girls between the ages of 14 and 19 dropped by 56 percent, even though only one-third of teenage girls in the U.S. have been vaccinated with the full three-dose course. HPV is the most common sexually transmitted virus. An estimated 75 percent to 80 percent of men and women are infected during their lifetime, but most do not develop cancer.
For more, we turn to Dr. Anne Schuchat of the CDC. She's the director of its Center for Immunization and Respiratory Diseases.
And, Dr. Schuchat, welcome.
How significant is this study?
DR. ANNE SCHUCHAT, Centers for Disease Control and Prevention: This is really exciting news, Margaret.
We have a vaccine that can prevent cancer, and we already have great results of the impact it's having in teenaged girls so far.
MARGARET WARNER: And did you expect to see this significant a reduction in such a short period of time, especially when all teenaged girls in America are not vaccinated?
ANNE SCHUCHAT: You know, I was surprised. We're vaccinating today in order to prevent cancers that will happen decades from now. We have also had very low uptake of the vaccine.
So this was an early look at the infection rate in teens, as well as other age groups, and we were really excited to see that we're already seeing this impact. We think the impact is greater than we were expecting with the low coverage that we have, and that's really good news, because, unfortunately, we don't have good coverage.
We haven't had good uptake of this vaccine so far. So, from my perspective, this is a real wakeup that we need to do better and get this vaccine out to all the teens in the country.
MARGARET WARNER: So tell us about how many teenaged girls are getting this vaccination? When do you recommend they get it? And when you say there hasn't been enough of an uptake, what do you mean?
ANNE SCHUCHAT: We recommend that teenage girls and boys receive the HPV vaccine series starting at age 11 or 12.
So far, only about half of the girls in the 13-to-17-year-old age group have received one dose of vaccine, and only about a third have received all three doses. Our recommendation for boys is fairly new, so we haven't really begun getting good results on that yet.
Some people wonder whether we can do a good job at vaccinating teenagers. You know, we have really high vaccination rates for infants and toddlers in the U.S. But what we have seen is very good uptake of other teenage vaccines. Recently, the vaccine against whooping cough, or pertussis, the vaccine against meningitis, those are both close to 80 percent uptake in the teenage years.
But, for HPV, we're really stuck at this one-third of girls with the full series, and only half with even one dose. We know we can do better, and we need to.
MARGARET WARNER: I want to get more into why, why the resistance, why it isn't bigger.
But first of all, remind us of -- I reported in the introduction that 75 percent to 80 percent of Americans get this HPV at some point in their lives, but how many of those cases turn into cancer?
ANNE SCHUCHAT: Right.
We think that about 19,000 women gets an HPV-related cancer every year. And about 12 -- I'm sorry -- about 8,000 men get an HPV-related cancer each year. Most of the -- the most common type of HPV-related cancer in women is cervical cancer.
The most common type of HPV-related cancer in men is throat cancer. So, one thing that we like to say to put this in perspective is, with the level of vaccination coverage we have right now, we are missing the chance to prevent a lot of cancers in girls.
We know that if we could raise our coverage from about 30 percent to the 80 percent figure that's our target, every year, we could prevent 4,400 cervical cancers and 1,400 fatal cervical cancers in girls. So one of the things that keeps me up at night is how are we going to improve our program, because every year our program stays at this low level, another 4,400 cervical cancers will happen.
MARGARET WARNER: So, what do you think explains the difficulty you have had in getting more American families to give this to their daughters?
ANNE SCHUCHAT: I think this is a complex issue.
Of course, there's been a lot of media attention to HPV vaccine. But one of the things we're finding in our research is that clinicians, doctors and nurses, are not giving strong recommendations. They're kind of sending mixed signals or mixed messages. I don't think the pediatricians in the country have really realized that they're the ones who can prevent cancers in this population.
The cancers show up later on in life. The pediatricians don't treat the cancers, but it's that time period, the teenage years, where we really need to give the vaccine out. We give the vaccine out before infection to prevent the disease and the cancers that can occur.
A lot of parents, and even some providers are wondering, can't we just wait until they're sexually active? Why do we have to do this or talk about this now at this early age? But it's just critical to get the vaccine in before sexual activity begins.
MARGARET WARNER: When this vaccine was first introduced, there was some controversy, especially among more conservative-minded people, that it would encourage early sexual activity or there might be health risks. How much of a factor do you think that kind of resistance is, and what do you say to parents who have those concerns?
ANNE SCHUCHAT: There's no evidence to suggest that vaccinating against HPV will change sexual behavior patterns in the future.
What I say to people is, how can you not want to prevent cancer in your daughter or son? As a clinician, as a parent, as a community member, how can we not want to use an anti-cancer vaccine?
MARGARET WARNER: All right, well, Dr. Anne Schuchat, thank you very much for joining us.
ANNE SCHUCHAT: My pleasure. Thank you, Margaret.