Objective: To estimate the global and regional distribution of HIV-1 subtypes and recombinants between 2000 and 2007.
Design: Country-specific HIV-1 molecular epidemiology data were combined with estimates of the number of HIV-infected people in each country.
Methods: Cross-sectional HIV-1 subtyping data were collected from 65 913 samples in 109 countries between 2000 and 2007. The distribution of HIV-1 subtypes in individual countries was weighted according to the number of HIV-infected people in each country to generate estimates of regional and global HIV-1 subtype distribution for the periods 2000–2003 and 2004–2007.
Results: Analysis of the global distribution of HIV-1 subtypes and recombinants in the two periods indicated a broadly stable distribution of HIV-1 subtypes worldwide with a notable increase in the proportion of circulating recombinant forms (CRFs), a decrease in unique recombinant forms (URFs) and an overall increase in recombinants. In 2004–2007, subtype C accounted for nearly half (48%) of all global infections, followed by subtypes A (12%) and B (11%), CRF02_AG (8%), CRF01_AE (5%), subtype G (5%) and D (2%). Subtypes F, H, J and K together cause fewer than 1% of infections worldwide. Other CRFs and URFs are each responsible for 4% of global infections, bringing the combined total of worldwide CRFs to 16% and all recombinants (CRFs along with URFs) to 20%.
Conclusion: The global and regional distributions of individual subtypes and recombinants are broadly stable, although CRFs may play an increasing role in the HIV pandemic. The global diversity of HIV-1 poses a formidable challenge to HIV vaccine development.
aNuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Oxford, UK
bEpidemiology and Analysis Division, UNAIDS, Switzerland
cWHO-UNAIDS HIV Vaccine Initiative, World Health Organisation, Geneva, Switzerland.
Received 6 August, 2010
Revised 11 November, 2010
Accepted 22 November, 2010
Correspondence to Dr Joris Hemelaar, Nuffield Department of Obstetrics and Gynaecology, University of Oxford, The Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK. E-mail: firstname.lastname@example.org