Japanese women’s health is increasingly at risk as public-health policy is driven by conspiracy theories, misguided political interference and bureaucratic caution. This is particularly evident in the government’s handling of the human papillomavirus (HPV) vaccine to protect against cervical cancer.

In June 2013, just two months after the HPV vaccine was included in the National Immunization Program, the Japanese government made the unusual and perplexing decision to keep the vaccine in the NIP but suspend “proactive” recommendations...