# Post-licensure safety surveillance of 9-valent human papillomavirus vaccine using the vaccine adverse event reporting system, 2014–2024

## TL;DR

This study analyzed safety reports of the 9vHPV vaccine from 2014 to 2024 to identify any new safety concerns.

## Contribution

The study provides the first decade of post-licensure safety data for the 9vHPV vaccine using VAERS.

## Key findings

- Most adverse events following 9vHPV vaccination were nonserious, with syncope and dizziness being common.
- Disproportionality analysis identified six potential safety signals, including anaphylactic shock and POTS.
- Deaths were rare and lacked sufficient documentation to establish causality.

## Abstract

On December 10, 2014, the Food and Drug Administration (FDA) licensed the 9-valent human papillomavirus vaccine (9vHPV) for prevention of HPV-related cancers and genital warts. This study aimed to summarize and characterize the first decade of post-licensure surveillance reports of 9vHPV submitted to the Vaccine Adverse Event Reporting System (VAERS).

We analyzed VAERS reports following 9vHPV administration in the U.S. during December 2014 through December 2024. Disproportionality analysis was conducted using the reporting odds ratio (ROR) to identify potential safety signals. Reports were categorized by sex, age, seriousness, and clinical outcomes.

The VAERS received 23,499 reports following administration of 9vHPV: 46.7% were from females, 25.7% from males, and 27.6% with unreported sex. Overall, 92.5% of reports were nonserious. Syncope, dizziness, loss of consciousness and pallor were most common AEs among nonserious reports. Headache, dizziness, pain and syncope were commonly reported serious AEs. Disproportionality analysis identified six MedDRA PTs that were disproportionately reported following 9vHPV vaccination: anaphylactic shock, postural orthostatic tachycardia syndrome (POTS), dizziness postural, complex regional pain syndrome (CRPS), premature menopause and acute disseminated encephalomyelitis (ADEM). Deaths (N = 57) were rare and most lacked sufficient medical documentation to establish causality.

The safety profile of 9vHPV over its first decade of use remains consistent with pre-licensure data, with most AEs being nonserious and self-limiting. Disproportionality analysis identified potential safety signals warranting further investigation but did not confirm causality. Continuous surveillance is necessary to further evaluate these rare events and ensure the ongoing safety of 9vHPV.