Japan alone is going backwards in time

Background: In Japan, the Ministry of Health, Labour, and Welfare decided to temporarily suspend recommendation of HPV vaccination in June, 2013. As a result, disparities in HPV vaccination rates have occurred, depending on an unfortunate year of birth, leading to predicted disparities in HPV infection rate at the age of 20. Materials and Methods: In this study, we estimated the cervical cancer incidence as a ratio of lifetime HPV infection risk. We assumed that “the frequency of cervical cancer occurrence throughout the lifetime of young females who did not have opportunities (born in 1993) to be vaccinated could be defined as 1”. The lifetime risk of cervical cancer was assumed to correlated with the risk of HPV infection throughout a lifetime, which was assumed to correlate with the rate of experiencing sexual intercourse before HPV vaccination. Results: If recommendation for the vaccine does not restart until 2020, then the females born between 2000 and 2003 will likely remain unvaccinated, as they will be above the age for government-paid vaccination by the time vaccination restarts. If the vaccination restarts in 2020 and the cumulative vaccinated rate after resuming vaccination encouragement in girls is 70%, the estimated risk of cervical cancer among girls (born in 2008 or later) will decrease to 0.58. Supposing that HPV vaccination for girls aged 12-16 during encouraged suspension, in addition to female children aged 12-16 at the time of encouraged resumption that restarts in 2020, the risk of cervical cancer among females who were born in 2000-2003 will be lower than the scenario of HPV vaccination only for young females aged 12-16 that restarts in 2020. Conclusions: This cohort of young women, if a significant intervention is not begun soon, will present an increase in regards to the future onset of cervical cancers. We must all be aware that Japan alone is going backwards in time.

HPV vaccine; Suspension of governmental recommendation; Cervical cancer risk; Birth year; Prediction.

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