Human immunodeficiency virus type 1 (HIV-1) subtype C appears to be spreadi
ng more rapidly relative to other subtypes of HIV-1 and is responsible for
most new infections in countries with emerging epidemics. In southern Afric
a, HIV-1 seroprevalences are high and almost exclusively attributed to subt
ype C infections. It is also the most dominant subtype in India and parts o
f China and, although the HIV seroprevalences in these regions are lower, t
he total number of infections is high.(1) It is estimated that 10 million p
eople are infected with HIV-1 subtype C through heterosexual and perinatal
transmission. Vaccine developers are now focusing on this subtype in an att
empt to curb its continued expansion. Compared to HIV-1 subtype a, which do
minates in the U.S.A. and Europe, considerably less is known about subtype
C viruses, although recent data indicate that they show distinct features.
This paper focuses on what is currently known about subtype C and how this
might influence the global spread and design of a vaccine.