Global and regional epidemiology of HIV-1 recombinants in 1990–2015: a systematic review and global survey

Abstract

BackgroundGlobal HIV-1 genetic diversity and evolution form a major challenge to treatment and prevention efforts. An increasing number of distinct HIV-1 recombinants have been identifiedworldwide, but their contribution to the global epidemic is unknown. We aimed to estimate the global and regional distribution of HIV-1 recombinant forms during 1990-2015. MethodsWe assembled a global HIV-1 molecular epidemiology database through a systematic literature review and a global survey. We searched PubMed, EMBASE (Ovid), CINAHL (Ebscohost), and Global Health (Ovid) for HIV-1 subtyping studies published from Jan 1, 1990, to Dec 31, 2015. Unpublished original HIV-1 subtyping data was collected through a survey among experts in the field who were members of the WHO-UNAIDS Network for HIV Isolation and Characterisation. We included prevalence studies with HIV-1 subtyping data collected during 1990-2015. Countries were grouped into 14 regions and analyses conducted for four time periods (1990-99, 2000-04, 2005-09 and 2010-15). The distribution of circulating recombinant forms (CRFs), and unique recombinant forms (URFs) in individual countries was weighted according to the UNAIDS estimates of the number of people living with HIV in each country to generate regional and global estimates of numbers and proportions of HIV-1 recombinants in each time period. The systematic review is registered with PROSPERO, number CRD42017067164.

Identification of CRF89_BF, a new member of an HIV-1 circulating BF intersubtype recombinant form family widely spread in South America

“…Recombination has contributed extensively to the generation of genetic diversity in the HIV-1 pandemic 13 , 14 . Recombinant forms are generated in individuals infected with two or more HIV-1 clades.…”

“…Those found in a single individual or a single epidemiologically-linked cluster are designated unique recombinant forms (URFs) and those found in three or more epidemiologically-unlinked individuals are designated circulating recombinant forms (CRFs) 15 , of which 105 have been described in the literature. The proportion of CRFs has increased over time in the HIV-1 pandemic, representing around 17% infections in 2010–2015 14 . Among identified CRFs, the most numerous are those derived from parental strains of subtype B and subsubtype F1, of which 16 have been reported, most of them originated in South America.…”

Genetic Characterization of a New HIV-1 Sub-Subtype A in Cabo Verde, Denominated A8

“…The global spread of HIV-1 group M in the second half of the 20th century has led to a complex and constantly changing distribution of subtypes and recombinant forms. Subtype A is responsible for about 10% of the HIV-1 infections worldwide, being found mainly in East Africa [19]. The characterization of the first A sub-subtypes occurred in 2001, distinguishing A1 and A2 [20].…”

“…Among the 100 CRFs already described until January 2021, subtype A is present in 59, some of them being part of a complex CRF involving three or more subtypes or CRF01 or CRF02 and other subtypes [4]. Among the circulating recombinant forms, the most widespread in the world are CRF01_AE and CRF02_AG, which are responsible for 5.3% and 7.7% of HIV-1 group M infections, respectively [19].…”

“…The continuous monitoring of molecular epidemiology in Cabo Verde and worldwide is extremely important since HIV diversity can impact diagnosis, viral load measures, drug resistance, responses to antiretroviral treatment, pathogenesis, vaccine design, immune response, and viral escape [19].…”