On June 16, the Supreme Court ruled that government-sponsored inoculations were responsible for infecting five people with the hepatitis B virus. It ordered the government to pay 5.5 million yen to each in compensation. Separately, on June 21, the Osaka District Court ordered the state, a drug maker and its subsidiary to pay a combined 256.3 million yen in compensation to nine of 13 plaintiffs infected with the hepatitis C virus from a blood-coagulation product. Both rulings underline the need for the government to enact measures to maintain the health of infected people.

In the hepatitis B case, the top court determined that repeated use of needles in inoculations transmitted the virus. Although the government had known since around 1951 that reuse of needles and syringes could spread hepatitis B, it didn't ban the practice until 1988. The plaintiffs received vaccinations between 1951 and 1983. The ruling also decided that people can file damage suits within 20 years from the discovery of their infection -- not from the time of their vaccination.

In the hepatitis C case, the court found illegality in the following facts: The drugmaker increased the risk of infection when it changed the anti-virus method used to produce fibrinogen, a coagulant, in 1985. The government then failed to restrict the use of the coagulant following an outbreak of infections in Aomori Prefecture in 1987. It also hastily approved a new type of the same blood coagulant the same year.