THE median survival time after Aids was diagnosed increased four times from 1984 to 1995 thanks to drug therapy, a study released on Tuesday in the Journal of the American Medical Association said. People diagnosed with Aids by the presence of an opportunistic illness in 1984 lived a median of another 11 months. But by 1995, that time had expanded to 46 months. The authors of the study attributed the longer survival chances to “improvements in antiretroviral therapy and an increase in the proportion of persons receiving therapy. The majority of the world’s Aids sufferers live in Africa.