Abstract
BackgroundThe Japanese Government settled a class litigation case with hepatitis B virus (HBV) carriers who claim to have been infected through needle/syringe sharing in childhood mass vaccination with a blanket compensation agreement. However, it is difficult to estimate how many of the present HBV carriers were infected horizontally from mass vaccination and how many were infected vertically from mothers.MethodsA mathematical model to predict the risk of infection through needle/syringe sharing in mass vaccination was proposed and a formula was developed. The formula was presented in a logarithmic graph enabling users to estimate how many people will be infected if a needle/syringe is shared by how many people for how many times under certain probability of infection. The formula was then applied to the historical data of mass tuberculin skin tests (TSTs) and BCG inoculation, from which a best estimate of how much needle/syringe sharing was practiced in different birth cohorts was determined.ResultsFor the oldest cohort born between 1951 and 1955, the prevalence of HBV carriers—0.65% at birth through vertical transmission—more than doubled in 1995 (1.46%) through horizontal transmission. If the probability of infection through needle/syringe sharing is assumed to be 10%, it is theoretically likely that an average of five or more people shared a needle/syringe four times to achieve the prevalence of HBV carriers in 1995. However, for the youngest cohort born between 1981 and 1985, the effects of needle/syringe sharing were negligible because the later prevalence of HBV carriers was lower than the prevalence at birth.ConclusionsMore than half of the HBV carriers born in the early 1950s might have contracted the disease by mass vaccinations. Japan’s experience needs to be shared with other countries as a caution in conducting mass vaccination programs under scarce needle/syringe supply (291 words).
Highlights
The Japanese Government settled a class litigation case with hepatitis B virus (HBV) carriers who claim to have been infected through needle/syringe sharing in childhood mass vaccination with a blanket compensation agreement
More than half of the HBV carriers born in the early 1950s might have contracted the disease by mass vaccinations
The Government accepted another settlement with the HBV plaintiffs in June 2011 with a blanket compensation agreement: Awarding the same damages to all HBV carriers who had been infected through needle/ syringe sharing in childhood mass vaccination [5]
Summary
The Japanese Government settled a class litigation case with hepatitis B virus (HBV) carriers who claim to have been infected through needle/syringe sharing in childhood mass vaccination with a blanket compensation agreement. The Government accepted another settlement with the HBV plaintiffs in June 2011 with a blanket compensation agreement: Awarding the same damages to all HBV carriers who had been infected through needle/ syringe sharing in childhood mass vaccination [5]. The potential financial burden of the blanket compensation could be gigantic given the high prevalence of HBV among the Japanese population, and the unknown prospect of how many were infected from needle/syringe sharing in mass vaccination and how many were not. I cannot answer correctly about experiences that happened such a long time ago...”
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
