Dr. Michiaki Takahashi, whose experience caring for his 3-year-old son after the boy contracted chickenpox led him to develop a vaccine for the virus that is now used all over the world, died on Monday in Osaka, Japan. He was 85. The cause was heart failure, said his longtime secretary, Maki Fukui. In 1964 Dr. Takahashi, who had spent several years studying the measles and polio viruses in Japan,
