Prevalence of HPV vaccine-associated symptoms in unvaccinated Japanese adolescents: A descriptive study from the...

In Japan, the proactive recommendation of human papillomavirus (HPV) vaccination was suspended in 2013 and resumed in 2022, with the HPV vaccination coverage rate slow to recover following this 9-year pause. The purpose of this study was to calculate the prevalence of diverse symptoms (DS) similar to adverse events following HPV vaccination in unvaccinated individuals.

This population-based descriptive study utilized data from the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) study database, which links National Health Insurance claims and immunization registries in four Japanese municipalities. Unvaccinated persons aged 10-19 years with claims from April 2017 to March 2022 were included. DS were defined using ICD-10 codes for 27 symptoms previously identified in the literature, with persistence exceeding 3 months considered indicative of onset. Cases with identifiable underlying disease were excluded by consensus review of pediatricians. Prevalence of DS was calculated by the fiscal year, age group, and sex.

DS occurred in 1891 cases. The overall prevalence of DS was 0.15 %, and prevalence was slightly higher in females than males. The most common symptoms were skin problems (in males aged 10-14 years, 0.83 %), sleep disorders (females aged 15-19 years, 0.44 %), headache (females aged 10-14 years, 0.40 %), and menstrual irregularities (females aged 15-19 years, 0.38 %). No substantial variations in prevalence were observed across municipalities or during the COVID-19 pandemic.

Our results provide objective evidence of DS even in Japanese adolescents who have not received the HPV vaccine. These results could help support improving HPV vaccine coverage in Japanese adolescents.