New HPV4 Vaccine Generally Safe

The quadrivalent human papillomavirus vaccine did not result in any new adverse events, aside from an increased risk of same-day syncope and skin infections in a 2-week period after injection.

Researchers analyzed the medical records of 189,629 female patients aged 9 years to 26 years who received the vaccine between August 2006 and March 2008 in an attempt to examine the risk of emergency department visits associated with the vaccine.

Adverse events were separated according to the time of occurrence: same-day, within 14 days, and within 60 days.

After isolating 50 diagnostic categories with significantly elevated odds ratios, researchers determined that all but same-day syncope and skin infection within 14 days were present before vaccination. 

Odds ratios for skin infections and syncope were 1.8 (95% Cl, 1.3 to 2.4) and 6.0 (95% Cl, 3.9 to 9.2), respectively. 

The skin infections, they noted, were likely predominantly site reactions to the vaccination, while syncope may not have been caused by the vaccine but simply the result of receiving an injection, saying, "Immunization and injections in general have a known association with syncope (particularly in this age group)."

Overall, “this study did not detect evidence of new safety concerns among females 9 to 26 years of age secondary to vaccination,” they concluded.

-Michael Potts