Time to resume active recommendation of the HPV vaccine in Japan

Changing trends in HPV vaccination in Japan

After the Japanese Ministry of Health, Labor and Welfare (MHLW) suspended its recommendation for the human papillomavirus (HPV) vaccine in June 2013, the rate of members of the new target population receiving of at least one of three doses of HPV vaccine declined, reaching 0.3% in 2016. Recently, however, the monthly number of vaccines delivered to healthcare facilities has significantly increased, from 878 doses over December 2016–April 2017 to 35,396 doses over January–March 2021. This may be due to governmental efforts to convey information about the HPV vaccination to the eligible population and their caregivers, as well as local educational programs, despite ongoing suspension of the recommendation. The incidence of reported adverse events per vaccine dose has not increased since 2016. While governmental recommendation of the HPV vaccination remains essential for optimal vaccine coverage, the recent increase in the number of doses delivered to healthcare facilities is promising.

Risk factors for HPV infection and high-grade cervical disease in sexually active Japanese women

In Japan, recommendations for HPV vaccines were suspended in 2013 due to unfounded safety fears. Although vaccine opponents claim modifying sexual behavior can prevent cervical cancer, no comprehensive data exist on sexual behavior and the risk of high-grade cervical disease in a Japanese population. This study investigates sexual behavior and the risk of HPV infection and cervical disease in 3968 women aged 20–41 yrs undergoing cervical screening between April 2014 and March 2016. Mean age at first intercourse was 18.4 yrs ± 2.8 and 32% of women reported ≥ 6 lifetime sexual partners. In regression analyses, number of partners was a significant risk factor for HPV infection. However, for high-grade disease (CIN2+), when HPV genotype was adjusted for, number of partners was not statistically significant. The greatest risk factor was an HPV16/18 infection (adjusted odds ratio 113.7, 95% CI: 40.8–316.9). In conclusion, we found that having an HPV16/18 infection and not sexual behavior was the most significant risk factor for high grade cervical disease in young Japanese women. These infections can be prevented by a highly effective vaccine and we recommend that the Japanese government resume proactive recommendations for the HPV vaccine immediately.