The Many Epidemiological Faces of AIDS With Special Reference to Hong Kong and Implications for Prevention and Control

Abstract

There are global differences in the epidemiological picture of the acquired immunodeficiency syndrome (AIDS) and its virus the human immunodeficiency virus (HIV). In Central Africa, AIDS has occurred predominantly in the sexually active age group, with a male to female ratio of 1.1: 1. The infection has been transmitted primarily by promiscuous heterosexual activity. In contrast, in the USA, the major groups at risk are male homosexuals, intravenous drug abusers and haemophiliac patients. Most of the infections have also occurred in the sexually active age group of 20 to 39 years, but the male to female ratio of reported cases was 19: 1. Similar risk groups have been affected in most of the developed countries in America, Europe and Australasia.

In Hong Kong, the three imported cases were all males with histories of sexual encounters abroad. Two were self-professed homosexuals or bisexuals, and the third admitted heterosexual contact with prostitutes. HIV infection has not been detected in intravenous drug abusers. Of the 61 HIV infections detected, 44 (72%) were in haemophiliac patients and 12 (19.8%) In homosexual or bisexual men. Only two infections were seen in women infected by transfusion of blood components in 1984 when safer products were unavailable.

Early preventive measures were taken in Hong Kong, including establishing an AIDS Expert Advisory Committee that informed the public about the facts on AIDS and gave clear guidelines to health care personnel. They were effective in averting the emotive reactions and hysteria to AIDS encountered in many developed countries. In recognition of the importance and need for epidemiological data, a seroepidemiologlcal programme was initiated in April 1985 to identify the groups infected and the extent of the infection. Universal blood donor unit screening for HIV antibody and the introduction of heat-treated Factor VIII were measures implemented to reduce parenterally acquired infections. An AIDS Education and Publicity Committee has also been assembled to heighten public awareness and to disseminate knowledge on the measures available to reduce the risk of infection. An anonymous and confidential AIDS Counselling and Consultation Clinic was established to provide an alternative testing site and to of fer advice and counselling to individuals at risk of infection.