M 21: Benefit-Risk Assessment of HPV Vaccination Program in Japan
Student, Maste's course
Gifu Pharmaceutical University Japan
We evaluated quantitatively the benefit-risk of human papillomavirus (HPV) vaccine in Japan to assess suspended Japanese HPV vaccination program resulting from media’s numerous reports on adverse events, which is different from other countries and criticized by WHO.
To quantitative risk aspects, we surveyed public data and compared with routine vaccines. The Burden Index was calculated using disability-adjusted life year and compared between vaccination and non-vaccination. To assess benefit aspects, we surveyed incidence rate of cervical cancer in the US.
In approval data package, the incidence of serious adverse events for HPV vaccine was 1.51%, whereas that of Polio vaccine and Diptheria-Pertussis-Tetanus (DPT) vaccine was 8.70% and 8.33%, respectively. In post marketing period, we visualized risk of HPV vaccine as well as other 6 routine vaccines using the risk-map with calculated frequency from Japanese Adverse Drug Event Report database adjusted by severity judged by three independent researchers. HPV vaccine has bigger risk than Influenza, Measles-Rubella, DPT and Japanese encephalitis vaccines. On the other hand, it has less risk than Tuberculosis and Polio vaccines. Estimated Burden Index (BI) in 10 to 44 years old women were 2.847 x 10-2 BI by adverse events in HPV vaccination group which was less than BI by cervical cancer in non-vaccination group (5.548 x 10-2 BI). The incidence rate of cervical cancer in specific age group has been decreasing since HPV vaccination was started in the US therefore the quantitative data for benefit of HPV vaccine has been accumulated.
Our results indicated that HPV vaccination has certain risks as equal as other routine vaccinations both before and after approval. Moreover BI could clearly show that the risk of HPV vaccination lowed risk of cervical cancer in non-vaccination group. Recent data of decreasing the incidence of cervical cancer showed the benefit of HPV vaccination. Thus, HPV vaccination can reduce risk and provide benefit, so it may increase the quality of life. The risk of HPV vaccination may be exaggerated in Japan, therefore the suspended decision of HPV vaccination program by Japanese MHLW might be questionable. Since suspension of HPV vaccination program in Japan in 2013, many Japanese women hesitate to receive HPV vaccine. We should choose whether to get HPV vaccination or not based on reliable information. However it is not enough quantitative data to estimate the benefit-risk balance of HPV vaccination. Further investigations, including the global assessments from various aspects, are required.