Geographic and population distributions of HIV-1 and HIV-2 circulating subtypes: A systematic literature review and meta-analysis (2010–2021)

BACKGROUND: HIV continues to be a major source of morbidity and mortality. Among the main challenges faced by prophylactic HIV vaccine development are the high rates of genetic mutation and recombination during HIV replication. This produces highly heterogeneous strains of HIV that often escape immune responses or treatment. Hence, information on geographic and population-specific HIV subtype (clade) distributions are crucial. We characterize HIV-1 and HIV-2 subtypes across geography and key populations based on a systematic literature review covering the past decade. METHODS: We searched PubMed, EMBASE, and CABI Global Health for peer-reviewed publications reporting HIV-1 or HIV-2 subtype prevalence data between January 2010 and June 2021. We included publications in any language across all regions in any population, irrespective of age, gender, ethnicity, CD4 count, viral load, ARV treatment regimen, or coinfections. RESULTS: A total of 454 studies across 91 countries were included. Globally, CRF/URFs accounted for 29% of all circulating HIV-1, followed by subtypes C (23%) and A (17%). Most papers reporting key population subtype breakdowns (n=104) focused on men who have sex with men (MSM) and people who inject drugs (PWIDs), where 62% and 38% of HIV infections were CRF/URFs, respectively. There was a 25% increase in other CRFs (not including CRF01_AE or CRF02_AG) prevalence between 2010–2015 and 2016–2021 in Latin America and the Caribbean. CONCLUSIONS: The HIV subtype distribution from this review follows those seen elsewhere, though with an increasingly higher prevalence of CRFs and a lower prevalence of subtype C. We found that reporting of HIV-2 data is often scarce.

• Epidemiology and Determinants of Health
  • Epidemiology
• Population(s)
  • Men who have sex with men
  • People who use drugs
  • General HIV+ population