Study Suggests HPV Vaccine Is Safe, but Doctors Wary
by ilene - August 19th, 2009 11:12 am
Study Suggests HPV Vaccine Is Safe, but Doctors Wary
By Alice Park, courtesy of TIME
Generally the fact that a vaccine appears to be as safe as the manufacturer had promised shouldn’t be news. It should be a given. But when it comes to the controversial vaccine against human papillomavirus (HPV), even the most straightforward data come with an asterisk.
The vaccine, called Gardasil and manufactured by Merck, is one of the first immunizations to protect against a cancer — in this case, cervical cancer, which is most commonly caused by infection with HPV. Because the virus is sexually transmitted, the Centers for Disease Control and Prevention (CDC) recommended in 2006 that girls get the vaccine at ages 11 and 12, before they become sexually active, so they have the best chance of avoiding the cancer and genital warts caused by HPV. States joined in, attempting to mandate HPV vaccination for school entry, but parents balked, in part because of concerns about encouraging promiscuity. It didn’t help that girls were prone to fainting after getting the shot or that more than two dozen girls died shortly after getting immunized.
To address those concerns, researchers at the CDC and the FDA, which keep track of adverse events related to vaccines once they are approved, now report in the Journal of the American Medical Association (JAMA) that the rate of adverse events associated with the 23 million doses of Gardasil administered since 2006 is similar to the prelicensing rate among the 21,000 girls and young women who tested it in clinical trials and to that of other vaccines.
That should be reassuring. But the study did find that users of Gardasil faint and develop blood clots more often than those receiving other shots. The clots are extremely rare, though. In about 90% of these cases, the girls may have been more vulnerable to developing clots because they smoked or were overweight or on birth control pills. "Was it that this age group also tends to have these risk factors or did the vaccine have some sort of role?" asks the CDC’s Dr. Barbara Slade, lead author of the paper. "We really don’t know."
It’s that uncertainty that is beginning to bother many physicians about the HPV vaccine. According to Dr. Charlotte Haug, editor in chief of the Journal of the Norwegian Medical Association and author of an editorial that JAMA…