Which is Safer: 9-Valent or Quadrivalent HPV Vaccine?

The safety profile of the 9-valent human papillomavirus (9vHPV) vaccine is similar to that of the quadrivalent HPV (qHPV) vaccine, according to a study published in Pediatrics. 

To determine the safety profile of 9vHPV, researchers analyzed data from 7 Phase II studies that included males and females aged 9 to 26 years. Participants received 3 doses of the vaccine (day 1, month 2, and month 6), with a total of more than 15,000 participants across the studies receiving 1 or more dose of 9vHPV. In addition, more than 7000 participants in 2 studies served as controls and received 1 or more doses of qHPV. 

During the studies, researchers recorded new medical conditions, as well as serious and nonserious adverse events. Pregnant patients were excluded, and patients who became pregnant after the start of the study did not receive any further vaccinations until the end of the pregnancy. Pregnancies that occurred after the study began were followed to outcome. 

Participants receiving the 9vHPV vaccine most commonly experienced adverse events at the injection site, such as pain, swelling, and erythema. Vaccine-related systemic adverse events such as headache and pyrexia were also reported. However, serious adverse events were rare (less than 0.1%), as were discontinuations (0.1%). 

Seven deaths occurred, but none of these were related to the vaccine. In addition, adverse outcomes in the pregnant patients were within general population ranges. None of the patients had an anaphylactic reaction to the 9vHPV vaccine. 

“The 9vHPV vaccine was generally well tolerated in subjects aged 9 to 26 years,” the researchers concluded. “Its additional coverage and safety profile support widespread 9vHPV vaccination.” 

The qHPV vaccine’s prelicensure database was comparable in size to the current safety database for 9vHPV. However, the 9vHPV database is currently unable to detect adverse events that occur at a rate of less than 1 in 5200. Rare adverse events will be evaluated in pharmacovigilance and postlicensure safety analyses, the authors stated. 

—Lauren LeBano 

Reference

Moreira ED, Block SL, Ferris D, Guiliano A, et al. Safety Profile of the 9-Valent HPV Vaccine: A Combined Analysis of 7 Phase III Clinical Trials. Pediatrics. 2016 Jul 15. pii: e20154387. [Epub ahead of print].