THE AIDS hotline run by the Department of Health entered the computer age yesterday in a bid to boost efficiency and cope with an increase in callers. The head of the department's AIDS prevention unit, Dr Lee Shui-shan, said that by offering a choice of recorded messages or individual counselling, the computerised system would reduce the number of callers unable to get through. Calls to the department's hotline, started in 1987, had increased by about 20 per cent annually during the past three years as more people became aware of the disease, he said. On average, the hotline receives 1,344 inquiries a month. ''There are some stereotype questions that people like to ask and these can be answered by the telephone system, leaving counsellors to pay special attention to people who call for psychological support,'' Dr Lee said. By pressing the telephone button indicated, callers to the revamped hotline can listen to one of seven recorded messages in Cantonese and English on such topics as ''What is AIDS?'' and ''Women and AIDS''. Four nursing counsellors are available to help callers with more complicated questions, while the service will also fax information on government clinics for the treatment of venereal diseases. Only callers with touch-tone phones can access the recorded messages, but a spokesman for Proactive Technology Ltd, which designed the system, said people with pulse phones would be put through to the counsellors. Dr Lee refused to reveal the cost of the computerised system, saying the department would have a better idea of expenses after the two-month trial period. The executive administrator of AIDS Concern, Ms Lisa Ross, welcomed the new service, saying information about the disease should be available from a variety of sources. But she suggested there should be better co-ordination among AIDS hotlines in the territory to ensure there were no gaps in service. AIDS Concern runs a hotline on Thursdays and Saturdays from 7 pm to 10 pm. The Hongkong AIDS Foundation, which also operates a hotline and information service, welcomed the computerised system. The Department of Health's AIDS hotline number is 780 2211. Meanwhile, a survey of high-risk groups found that ignorance about AIDS could lead to an epidemic among sexually active youngsters. Mr Howard Cheng Chi-ho, senior lecturer in the department of applied social studies at Hongkong Polytechnic, said young people's misconceptions on AIDS was worrying. A total of 100 people from high-risk groups including intravenous drug users, prostitutes and their clients, homosexuals and sexually active youths were interviewed for the survey. Mr Cheng said at least half of the young people questioned thought AIDS could be transmitted by mosquito bites or by touching AIDS patients. Most of the youths did not talk seriously about AIDS and believed they would never catch it. Out of 12 males and eight females aged between 15 and 24 interviewed, all but one were sexually active. Mr Cheng said serious action should be taken to prevent the spread of AIDS among young people. The Government had ''no long-term, genuine and practical policy on youth'', he said. He called for a discussion involving the Government, AIDS support groups and youth groups to work out new strategies.