NEW YORK (Reuters Health) – In general, the quadrivalent human papillomavirus vaccine (qHPV, Gardasil, Merck and Co.) licensed by the US Food and Drug Administration in June 2006 is no more likely than other commonly used vaccines to cause side effects, new research shows.

However, the vaccine was linked to higher rates of syncope and venous thromboembolic events relative to prelicensure data and rates with other vaccines.

“The significance of these findings,” the authors conclude, “much be tempered with the limitations (possible underreporting) of a passive reporting system.”

Using data from the Vaccine Adverse Event Reporting System, Dr. Barbara A. Slade, from the Centers for Disease Control and Prevention, Atlanta, and colleagues assessed the safety of qHPV following licensure and distribution.

A total of 12,424 reports of adverse events were logged, which corresponds to a rate of 53.9 reports per 100,000 doses distributed, according to a report in the Journal of the American Medical Association for August 19.

Of the reports, 772 (6.2%) documented a serious event, including death in 32 reports. The numbers of adverse event reports per 100,000 qHPV doses distributed were “8.2 for syncope, 7.5 for local site reactions, 6.8 for dizziness, 5.0 for nausea, 4.1 for headache, 3.1 for hypersensitivity reactions, 2.6 for urticaria, 0.2 for venous thromboembolic events, autoimmune disorders, and Guillain-Barre syndrome, 0.1 for anaphylaxis and death, 0.04 for transverse myelitis and pancreatitis, and 0.009 for motor neuron disease.”

As noted, the syncope and venous thromboembolic rates were higher than expected.

In an accompanying commentary, Dr. Sheila M. Rothman and Dr. David J. Rothman, from Columbia College of Physicians and Surgeons, New York, discuss the marketing of qHPV and the negative impact it may have had on adolescent health.

“As marketing of this HPV vaccine demonstrates, pharmaceutical company campaigns can undercut the most cost-effective and appropriate use of new agents to the detriment of adolescent health. By making this vaccine’s target disease cervical cancer, the sexual transmission of HPV was minimized, the threat of cervical cancer to all adolescents maximized, and the subpopulations most at risk practically ignored.”

Reference:
JAMA 2009;302:750-757,781-786.