American Medical News
By — Posted July 1, 2013
The human papillomavirus vaccine got a boost in June when a Centers for Disease Control and Prevention study reported that prevalence of the virus was cut in half among vaccinated teenage girls.
The decline surprised researchers, because just one in three girls has been vaccinated with the recommended three doses against HPV, the most common sexually transmitted virus.
“The decline is higher than expected. It is encouraging,” said Laurie Markowitz, MD, medical epidemiologist in CDC’s Division of STD Prevention and the study’s lead author.
The findings were posted online June 19 in The Journal of Infectious Diseases. The study found that cases of HPV decreased 56% among vaccinated female teens ages 14-19 from 2007 to 2010. Among other age groups, prevalence did not differ significantly.
Researchers attributed the decline in part to the vaccine, despite the low vaccination rate among girls. Herd immunity and changes in sexual behaviors also may have contributed, they said.
HPV is so common that nearly all sexually active men and women will get at least one type of HPV at some point in their lives. About 79 million Americans are infected, the CDC said.
The vaccine Gardasil, manufactured by Merck, is approved for boys and girls. Cervarix by GlaxoSmithKline is approved for girls only. The vaccine is administered in three doses, although early research indicates that fewer doses may be effective.
The CDC report comes amid worries about vaccine safety, including 42 deaths reported to the Vaccine Adverse Event Reporting System, a national surveillance system co-sponsored by the CDC and the FDA.
“The cause of these deaths has been very varied,” said Cindy Weinbaum, MD, MPH, senior adviser for vaccine programs in the CDC Division of Healthcare Quality Promotion. “It’s everything from cardiovascular to infectious, neurologic and hematologic. There’s no consistent pattern of deaths that have occurred after vaccination that would give us any cause to be concerned that the vaccine was responsible.”
Many U.S. parents have been hesitant to have their daughters vaccinated, while countries such as Rwanda have vaccinated 80% of girls in the recommended age range. For example, a study in the April issue of Pediatrics reported that 75% of teenage girls were not up to date with HPV immunization in 2010. More than 40% of their parents had no intention of completing the vaccine.
“This vaccine has a lot of emotional baggage,” said Rodney Willoughby, MD, a professor of pediatrics at the Medical College of Wisconsin in Milwaukee. “Physicians have to promote this, and when you are already two patients behind, you’re not going to pick a fight. … But evidence like this will lead to higher uptakes.”
But despite prodding and research, some parents remain reluctant.
“This is a perfectly safe vaccine, and any hesitancy over use is misplaced,” said Doug Campos-Outcalt, MD, chair of the Dept. of Family, Community and Preventive Medicine at the University of Arizona College of Medicine. “There will be a lot of regret later. There will be a generation of young women with cervical lesions wondering why they weren’t vaccinated.”