Is the catch‐up program of HPV vaccination for Japanese adult women effective or not?

Dear Editor,

“Reduction in HPV16/18 prevalence among young women with high‐grade cervical lesions following the Japanese HPV vaccination program” by Matsumoto et al1 provides important information for conducting a catch‐up vaccination program for the human papillomavirus (HPV) vaccine in Japan in the future. However, we disagree with the authors’ proposal that the catch‐up vaccination of women older than 20 years has no effect, for the following reasons. First, the study design did not compare the effect of HPV vaccination between the vaccination group and the nonvaccination group in healthy women. Second, the number of women in the vaccination group with cervical intraepithelial neoplasia grade 2‐3/adenocarcinoma in situ (17 and 66 women aged 21‐25 and more than 25 years at first vaccination, respectively) was extremely small. Moreover, we cannot strongly support this proposal of the authors because of the discrepancy with previous reports.

There are a few randomized, double‐blind, prospective cohort studies that evaluated the effect of vaccination on the persistent infection of HPV16 or HPV18 genotype in healthy women aged 15‐25 years, and all studies indicated that the vaccination was effective.2, 3

There are 2 randomized, double‐blind, prospective cohort studies that evaluated the effect of vaccination on the infection of HPV16 or HPV18 genotype in healthy women aged 26 or older.4, 5 The VIVIANE study reported that the reduction rate of persistent infection of HPV16 or HPV18 genotype in women aged 26‐35 years and 36‐45 years was 38.7% and 57.0%, respectively. Furthermore, a 80.1% and 67.2% reduction rate of persistent infection of HPV16 or HPV18 genotype was reported in women aged 26‐35 years and 36‐45 years with negative or low‐grade cytological results, respectively.5 In the second study in women aged 24‐45 years, Castellsagué et al. reported that the suppression rate of the persistent infection of HPV16 or HPV18 genotype was 42.8% and 86.2% in the intention‐to‐treat population and per‐protocol efficacy population, respectively.4 In August 2019, US Center for Disease Control and Prevention declared that vaccination should be considered if doctors determined that women were most likely to benefit.6

Japanese adult women who missed HPV vaccination because of the Ministry of Health, Labor and Welfare (MHLW)’s suspension of vaccine recommendation may doubt whether to vaccinate when the vaccine recommendation resumes in the near future. Thus, it is extremely important that the Japanese MHLW conducts the catch‐up program for adult women based on data from the Japanese population. We have initiated a nonrandomized, nondouble‐blind, prospective cohort study to compare the preventive efficacy of quadrivalent HPV6/11/16/18 vaccine between the vaccination group and nonvaccination group in Japanese healthy adult women aged 27‐45 years (trial registration nos. NCT04022148 and jRCTs051190039). We suggest that the Japanese MHLW should judge the efficacy of vaccination in Japanese adult women based on both the MINT study (the authors’ study) and HAKUOH study (our study).

Disclosure

The author has no conflict of interest.