Pediatricians Likely to Recommend New HPV Vaccine
When a human papillomavirus vaccine becomes available in the very near future, will pediatricians recommend it to patients and their parents? The answer is yes, according to recent research by Jessica Kahn, MD, MPH, of the Cincinnati Children's Division of Adolescent Medicine. For the vaccine to be widely accepted and used, pediatricians and family practice physicians will play a key role in education and endorsement.
Dr. Jessica Kahn talks with a teen patient about the benefits of the HPV vaccine.
HPV is a very common virus that is spread primarily through sexual contact. Experts believe that 75 to 80 percent of US adults have been exposed to at least one type of HPV at some point. One HPV vaccine was approved in June 2006 for 9- to 26-year-old girls and women, and will likely be available for use later this year. The other vaccine is expected to be approved by the FDA within the next year.
Both vaccines protect against two particularly aggressive varieties – HPV 16 and 18 – that cause 70 percent of all cervical cancers, as well as other types of cancer such as penile, anal, vulvar, oral and esophageal. One of the vaccines adds protection against HPV 6 and 11, the cause of nearly all genital warts in men and women. Cincinnati Children's participated in the multicenter clinical trials and also studied young women's attitudes toward the vaccine.
Although the Advisory Committee on Immunization Practices and the American Academy of Pediatrics have not yet finalized age guidelines, Dr. Kahn believes the targeted group will be 11- to 12-year-old girls. Because the vaccine prevents HPV – but does not treat it – the goal is to administer it before sexual activity has begun.
Nearly 100% Protection
"These vaccines provide nearly 100 percent protection against infection with the HPV types contained in the vaccines. But they won't have a significant public health impact unless they are given universally. Since the HPV vaccine probably will not be mandated for school enrollment, at least initially, prior experience has shown that uptake could be slow," Dr. Kahn explains.
"Many teens won't know about the vaccine, and parents may not ask, because most of them aren't aware that HPV is a sexually transmitted infection that causes cervical cancer. So health care providers will be key in getting the vaccine to teens. That's why we are particularly interested in physicians' knowledge and attitudes," says Dr. Kahn.
A survey of 1,000 pediatricians in 2004 revealed that three-quarters of those who responded would give the vaccine to their patients. They were more likely to recommend vaccination to girls and older teens, and also more likely to recommend the combined cervical cancer/genital wart vaccine over the cervical cancer vaccine alone.
These factors also influenced pediatricians' likelihood to recommend the vaccine: a higher estimate of sexually active adolescents in their practices; a higher number of young adolescents seen weekly; a higher level of knowledge about HPV; a greater likelihood to follow the recommendations of important individuals and organizations with respect to immunization; and fewer perceived barriers to immunization. A separate study of family physicians revealed similar attitudes.
Few Parental Concerns
Respondents said that the main barrier to vaccine administration would be perceived parental concerns. However, Dr. Kahn says the literature shows that most parents are supportive of HPV vaccination, and only a small percentage oppose it. "The main reason parents support vaccination is to protect their kids from cancer," she says. "Currently, there is no evidence that HPV vaccination will increase risky sexual behavior among adolescents, but we do need to study this issue." Dr. Kahn notes that follow-up data show that antibodies remain high more than four years after vaccination. "We don't know yet how long immunity will last, so we may discover that a booster is needed," she says.
"We've entered a new era of adolescent vaccines that present new challenges in terms of vaccine delivery and behavioral consequences of vaccination. I believe the HPV vaccine will become the primary prevention strategy against cervical cancer.
"Our goal is to maximize the public health impact of these vaccines to prevent HPV-related diseases, especially cervical cancer.
We want to maximize uptake by teens and parents and maximize recommendations by providers. We need to study whether vaccination has any impact on sexual or Pap screening behaviors so that we can create evidencebased educational messages to promote healthy behaviors after vaccination."
Dr. Kahn is director of research training and associate professor of pediatrics in the Division of Adolescent Medicine. Her study was published in the Journal of Adolescent Health (37:502-510, December 2005) and was supported by a grant from the National Institute of Allergy and Infectious Diseases.
