The Fukuoka District Court on Monday ordered the government to pay ¥12.5 million each to two chronic hepatitis B patients who argued that the 20-year compensation window the government set for victims infected in vaccination programs is unfair.

Under a special law, the government provides compensation payments to people who were infected with hepatitis B as a result of the systematic sharing of needles in past vaccination programs. The payments are reduced if the people do not take legal action within 20 years of developing symptoms.

The plaintiffs, who live in Fukuoka Prefecture, contracted hepatitis B through a mass early childhood vaccination program. Symptoms had improved for both at one point before they suffered relapses, one in 2004 and the other in 2008.

The men, one in his 60s and the other in his 50s, sued after their symptoms returned.

In the ruling, presiding Judge Akihito Katayama said that the relapses represent “new damage” and that the plaintiffs should therefore receive compensation.

The judgment is the first of its kind and could set a precedent for other lawsuits involving relapses of the disease or its symptoms.

According to the plaintiffs’ lawyers, about 80 people have sued the government over the vaccination programs and many haven’t taken action yet, which means the number could rise.

At the trial, the plaintiffs insisted the 20-year compensation window should be applied from the time their symptoms reoccurred. The government countered that people who developed hepatitis B symptoms 20 or more years ago have already lost their right to damages under the Civil Code.

Under the special law that took effect in 2012, people with chronic hepatitis receive a one-off benefit of ¥12.5 million if they file within 20 years, much more than the maximum of ¥3 million awarded to those who fail to do so in that time frame. Those affected must sue the government to be recognized as eligible for the payment.

Hepatitis B, caused by a virus that is transmitted through contact with blood or other bodily fluids, puts people at high risk of death from cirrhosis and liver cancer, according to the World Health Organization.

Children under 6 who become infected are the most likely to develop chronic infections, it says.

At least 400,000 people in Japan are believed to have the hepatitis B virus due to lax needle practices during group vaccination programs between 1948 and 1988. But only about 7 percent, or 31,439 people, have been recognized as eligible for payments based on the special law.