Global HIV Molecular Epidemiology Collaboration
The Global HIV Molecular Epidemiology Collaboration is a network of researchers focused on the surveillance of HIV genetic diversity worldwide. The extensive genetic variability of HIV poses challenges for diagnosis and treatment, and is a major obstacle to the development of effective vaccines. Continuous global surveillance of HIV diversity is crucial to understand the evolution and global spread of HIV, which informs developments in prevention and treatment necessary for tackling the HIV pandemic.
Background
The HIV pandemic remains a major global health challenge. In 2023, an estimated 39.9 million people were living with HIV, 1.3 million were newly infected, and 630 000 died from AIDS-related illnesses.
While two thirds of people living with HIV resided in sub-Saharan Africa in 2023, for the first time more new infections occurred outside sub-Saharan Africa than within, particularly in Eastern Europe and Central Asia, Latin America, and the Middle East and North Africa. Outside sub-Saharan Africa the vast majority of new infections occur among key populations, such as gay men and other men who have sex with men, sex workers, people who inject drugs, transgender people, and people in prisons and other closed settings.
Since its zoonotic transmission from chimpanzees to humans in central Africa during the 1900s, HIV-1 has diversified into ten distinct subtypes (A-D, F-H, and J-L), more than 150 circulating recombinant forms (CRFs), and unique recombinant forms (URFs). CRFs are recombinants that have been found in at least three epidemiologically unrelated individuals, whereas URFs are unique recombinants without evidence of onwards transmission. HIV-1 variants are differentially distributed around the world and key populations are associated with distinct HIV-1 variants.
Activities
The Global HIV Molecular Epidemiology Collaboration is led by Associate Professor Joris Hemelaar at Oxford Population Health. The Collaboration evolved out of the WHO-UNAIDS Network for HIV Isolation and Characterisation.
We collect and analyse global HIV subtyping data using systematic literature reviews and surveys. Our systematic literature reviews include published studies with original HIV subtyping data. Our global surveys capture as yet unpublished primary HIV subtyping data collected as part of independent studies conducted by researchers in the field of HIV molecular epidemiology.
With data on more than one million subtyped HIV samples compiled from 1990 to date, we generate timely updates describing the distributions of HIV-1 subtypes and recombinants across countries and time.
© Malavika Nair, Lucy Gettins, Matthew Fuller, Shona Kirtley, Joris Hemelaar, Global and regional genetic diversity of HIV-1 in 2010–21: systematic review and analysis of prevalence, The Lancet Microbe, Volume 5, Issue 11, 2024, 100912, ISSN 2666-5247 https://doi.org/10.1016/S2666-5247(24)00151-4.Regional distributions of HIV-1 variants 2016–21. (A) Regional distributions of HIV-1 variants, 2016–21. The relative surface areas of the pie charts are proportional to the numbers of people living with HIV in each region. (B) Regional distributions of other CRFs, 2016–21. The pie charts are equal sized to enable visualisation of distributions of other CRFs in regions with few people living with HIV with other CRFs. Countries were grouped into 14 regions and regions are differentially shaded on the world map. CRF=circulating recombinant form. Other CRFs=CRFs other than CRF01_AE, CRF02_AG, and CRF07_BC. URF=unique recombinant form. Unspecified recombinants=recombinants without further specification of CRF or URF.
We reported in Lancet Microbe that, in the period 2016‒21, the majority of global HIV-1 infections were subtype C (50.4%), followed by subtype A (12.4%), subtype B (11.3%), CRF02_AG (6.6%), CRF01_AE (5.4%), subtype G (2.9%), subtype D (2.6%), URFs (2.0%), other CRFs (1.9%), and CRF07_BC (1.2%). This reflected significant increases in global proportions of subtypes A and C, and CRF07_BC, and decreases in subtypes D and G, CRF02_AG, other CRFs, and URFs, compared to 2010 - 15. No changes were found for subtypes B and F, and CRF01_AE.
We found significant regional variations in the distribution of HIV-1 variants. While Central, West, and East Africa had high genetic diversity, Southern Africa, Ethiopia, and India were dominated by subtype C, the Caribbean, Latin America, North America, and Western and Central Europe were dominated by subtype B, Eastern Europe and Central Asia were dominated by subtype A, and Southeast Asia was dominated by CRF01_AE.
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