Nine-valent human papillomavirus vaccine shows favourable safety profile

Safety data of the 9-valent human papillomavirus vaccine (9vHPV) from the Vaccine Adverse Event Reporting System (VAERS) during the first 3 years of its licensure in the United States have shown neither new or unexpected safety signals, nor unusual reporting patterns for clinically important adverse events (AEs), as reported in a study. Furthermore, the safety profile of the vaccine is similar to that of its quadrivalent predecessor.

VAERS documented 7,244 AEs following receipt of 9vHPV. Of the AEs, 31.2 percent occurred among females and 21.6 percent among males; sex was not reported in 42.7 percent.

Majority (97.4 percent) of the AEs were nonserious, the most common being dizziness, syncope, headache and injection site reactions. These AEs occurred with similar frequency in men and women. There were two verified cases of deaths post-9vHPV treatment, although autopsy reports or death certificates suggested no evidence of a causal relationship with vaccination.

Roughly 28 million 9vHPV doses were administered during the study period, giving crude AE reporting rates of 259 reports per million doses distributed for all reports and 7 per million doses distributed for serious reports.

Empirical Bayesian data mining findings showed a significant association between 9vHPV and syncope and several types of vaccine administration errors (eg, administered at wrong age).