# HPV vaccine-related thyroid adverse events: temporal patterns and reporting trends

## TL;DR

This study examines possible links between HPV vaccination and thyroid disorders using adverse event reports, finding signals for hypothyroidism and autoimmune thyroiditis.

## Contribution

The study identifies specific thyroid-related adverse events associated with HPV vaccination using disproportionality analyses and temporal risk modeling.

## Key findings

- Hypothyroidism and autoimmune thyroiditis showed the strongest signals associated with HPV vaccination.
- Most thyroid adverse events occurred in females under 65 years old.
- HPV-4 vaccine was linked to 72.8% of reported thyroid adverse events.

## Abstract

Human papillomavirus (HPV) vaccination is essential for cervical cancer prevention, but concerns about thyroid-related adverse events (AEs) have emerged.

This pharmacovigilance study aimed to assess potential associations between HPV vaccination and thyroid disorders using spontaneous report data. Reports from the U.S. Vaccine Adverse Event Reporting System through 31 December 2024, were analyzed. Disproportionality analyses (PRR, ROR, BCPNN, MGPS) were performed, with subgroup analyses by gender, age, and vaccine type. A Weibull shape parameter model assessed the temporal risk pattern.

Among 60,840 HPV vaccine-related reports, 13 thyroid-associated AEs showed positive signals. Hypothyroidism (ROR = 11.65) and autoimmune thyroiditis (ROR = 4.26) were the strongest signals. Most cases occurred in females under 65 years. HPV-4 was linked to 72.8% of thyroid AEs. The cumulative reporting rate reached 69.1% within 180 days.

Our findings suggest a potential association between HPV vaccination and thyroid disorders, notably hypothyroidism and autoimmune thyroiditis. Continued pharmacovigilance and further mechanistic investigations are needed.