He hoped for results similar to those from the influenzae type b (Hib) vaccine. “We saw a dramatic decrease in the amount of acute epiglottitis,” he said. “We’re hoping that the same kind of monumental change occurs with the HPV vaccine.”
Explore This IssueJuly 2010
The latest study on Gardasil found an efficacy rate up to 100 percent in preventing genital warts among those not yet infected. That analysis included 17,622 females aged 15-26 enrolled in one of two randomized, controlled efficacy trials, with the vaccine or placebo given at day one, month two and month six. The average follow-up was 3.6 years (J Natl Cancer Inst. 2010;102(5):325-339).
Gardasil was approved in the U.S. in 2006 for females ages 9 to 26, and in 2009 for males ages 9 to 26. In Europe, it is approved for females ages 9 to 26 and males 9 to 15. The vaccine is also approved in many other countries.
The main target group in the U.S. includes teenage girls aged 11 and 12, so that they can be vaccinated before becoming sexually active. Studies have shown the risk of HPV infection in the U.S. soars after a young girl’s first intercourse, and 70 percent of girls have had sex by age 18 (BJOG. 2002;109(1):96-98; Adv Data. 2005;362:1-55).
But, as of the end of 2008, only 37.2 percent of girls in the U.S. aged 13 to 17 had received one or more Gardasil vaccinations, according to the Centers for Disease Control and Prevention’s (CDC) Morbidity and Mortality Weekly Report. Experts say there is hesitation among some primary doctors to encourage the vaccination, either because of lack of knowledge or concerns about safety.
As of Jan. 31, there were 15,829 reports of adverse events following Gardasil vaccination, recorded in the Vaccine Adverse Event Reporting System, an early warning system for possible harmful effects of vaccinations. But 92 percent of the events were non-serious, ranging from fainting to headache to nausea.
—Farrel Buchinsky, MD
The 8 percent of effects that were serious include Guillain-Barré Syndrome; deep vein thrombosis; and 49 deaths in females who have received Gardasil. The CDC issued a statement in April vouching for the safety of Gardasil.
“Experts have not found a common medical pattern to the reports of serious adverse events reported for Gardasil that would suggest that they were caused by the vaccine,” according to the CDC website. But there is still considerable hesitation about the vaccine, and vaccines in general, say doctors who treat RRP.