Cervical Cancer Vaccine Seems Safe
Aug. 19 -- TUESDAY, Aug. 18 (HealthDay News) -- The vaccine that protects against human papillomavirus (HPV), a cause of cervical cancer, appears safe, with relatively few serious side effects, according to a new U.S. government study.
The study, which included data from the voluntary Vaccine Adverse Event Reporting System (VAERS), found that the rate of serious adverse events for the vaccine, marketed under the brand name of Gardasil, was similar to data from earlier clinical trials, except for rates of fainting and blood clots.
For every 100,000 doses of HPV vaccine distributed, the study found 8.2 episodes of fainting and 0.2 episodes involving blood clotting. The study is published in the Aug. 19 issue of the Journal of the American Medical Association.
"Basically, we didn't see anything that surprising. This is a safe vaccine," said the study's lead author, Dr. Barbara Slade, a medical officer in the immunization safety office at the U.S. Centers for Disease Control and Prevention. "Syncope [fainting] is the most commonly seen adverse event."
As for the increased rate of serious incidents of blood clotting, Slade said that most of the girls or women who had such problems had other characteristics that increased their risk for clots.
"It's a complicated issue," she said. "Most of these girls had another risk factor for blood clots, but we don't want to dismiss the blood clots. We need to know if it's something that's truly unrelated, and we're recommending that this finding be looked at a little bit closer."
In June 2006, Gardasil was licensed for use in girls older than 9 years to prevent infection from four types of HPV. HPV is a virus known to cause genital warts and cervical cancer. Two types of HPV covered by the vaccine, HPV-16 and HPV-18, cause about 70 percent of cervical cancers worldwide. The vaccine is given in three doses.
In clinical trials conducted before licensing, researchers found that the rates of adverse events were similar in girls and young women who received the vaccine compared with those who received a placebo injection.
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