Emerging Trends of HIV Epidemiology in Asia

The main molecular trait of HIV-1 is the inherent capacity to vary, recombine, and diversify, whichgives it a clear edge to evade the human immune system and survive through the generation ofcomplex molecular forms, termed recombinants. In a setting of coinfection, molecular and biologicalinteractions between diverse HIV-1 subtypes may promote the emergence of circulating recombinantforms through the shuffling of viral genomes, which results in increased intra- and inter- host viralvariation and altered biological properties. The focus of this review is on Asia, which has the highestproportion of HIV-1 recombinants circulating worldwide, with the top in South and Southeast Asia,amounting to 89% of its total HIV-1 infection. The HIV-1 strains which are spreading in this geographicarea are CRF01_AE, subtypes B and C. Given the rapid spread and active establishment of some ofthe recombinant forms in Asia, it is essential to understand how they differ from their parental strains,the acquisition of certain molecular traits, and their biological attributes upon recombination, whichgive these strains an epidemiologic edge. The current epidemic provides strong evidence that theparental subtypes are being replaced via competition with possibly more versatile HIV-1 recombinantforms. This appears to be an ongoing phenomenon and has resulted in an HIV-1 epidemic shift, withthe expansion and dissemination of a wide variety of HIV-1 forms within this geographic region.