Since the first case of human immunodeficiency virus (HIV) infection in the
Republic of Korea (ROK) was detected in 1985, 876 HIV-infected patients ha
ve been reported, as of December 1998, The male to female ratio was 6.8,1,
and 87% of the patients were between 20 and 49 years of age. The major mode
s of transmission were sexual contacts, accounting for 86% of the cases (65
% heterosexuals and 21% homosexuals). Transmission through blood and blood
products accounted for 28 cases (3.2%), and vertical transmission for one c
ase. No cases among intravenous drug abusers were reported. The seroprevale
nce among the blood donors was approximately one in 100,000. Subtypes A, B,
C, D, E, and G of HIV-1 have been introduced into the ROK, and subtype B i
s the most predominant subtype. The frequency of the a deletion in the CCR5
gene, a coreceptor of HIV-1, was less than 1% among Koreans.