Since June 14th 2013, the Japanese Ministry of Health Labour and Welfare (MHLW) has suspended recommendations for the HPV vaccination program. The first cohort of adolescent girls vaccinated with HPV vaccine against HPV 16 and 18 at age 16 yrs (birth year 1994), reached the Japanese screening age of 20 in 2014. These girls, along with girls born between 1995 and 1999, were vaccinated between November, 2011 and March, 2013 with public funding from specific budgets of the national and regional government. In April, 2013, a National Immunization Program started, but sensational media reports adversely affected it without any scientific proof. Japan has no linkage of screening and vaccination programs unlike in Australia, the UK, Nordic countries and Canada, etc. Thus, using data from the Japan Cancer Society is the only way to obtain national data to evaluate population-based effectiveness of HPV vaccination in Japan.
A part of nationwide data on cervical screening results for women aged 20 to 29yrs (a total of 31,890 subjects) in 2014 was obtained from 15 branches of the Japan Cancer Society. At screening, women had to fill in a questionnaire about HPV vaccine status and this data was used to analyze the relationship between vaccine status and incidence of CIN3.
Among 31,890 women, 1,207 women were vaccinated and 30,483 women were unvaccinated. Overall 3.8% of the women had been vaccinated against HPV. In women aged 20 and 21 years, it was 32.3% and 7.5%, respectively. Among women vaccinated and unvaccinated, CIN 3 lesions were cumulatively detected in 1 case (0.08%) and 79 cases (0.26%) for 1 year, respectively. Thus, risk ratio on development of CIN 3 lesions was 0.31 [95%CI: 0.04-2.21], but not statistically significant.
This preliminary result may suggest the early impact of relatively effectiveness of HPV vaccination but further evaluation is warranted. It is necessary that the government and academia explains about the effectiveness and safety of the HPV vaccine based on scientific evidences with epidemiological surveillance. As GACVS has noted previously, policy decisions based on weak evidence, leading to lack of use of safe and effective vaccines, can result in real harm (1, 2).
1. http://www.who.int/vaccine_safety/committee/topics/hpv/Dec_2015/en/
2. http://www.who.int/vaccine_safety/committee/topics/hpv/GACVS_Statement_HPV_12_Mar_2014.pdf