The changing molecular epidemiology of HIV type 1 among northern Thai drug users, 1999 to 2002

Sodsai Tovanabutra, Chris Beyrer, Supachai Sakkhachornphop, Myat Htoo Razak, Gabriela L. Ramos, Tassanai Vongchak, Kittipong Rungruengthanakit, Pongpran Saokhieo, Kwanchanok Tejafong, Bohye Kim, Mark De Souza, Merlin L. Robb, Deborah L. Birx, Jaroon Jittiwutikarn, Vinai Suriyanon, David D. Celentano, Francine E. McCutchan

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


CRF01_AE and subtype B have dominated the HIV-1 epidemic in Thailand since 1989. We reported a new circulating recombinant form of HIV-1, CRF15_01B, as well as other unique CRF01_AE/B recombinants among prevalent HIV infections in Thailand. We sought to study this challenging molecular picture through assessment of subtypes among recent HIV-1 seroconverters in northern Thai drug users. A total of 847 HIV-1 seronegative drug users (342 IDU and 505 non-IDU) were enrolled, from 1999 to 2002, in a prospective study; 39 HIV-1 incident cases were identified and characteristics were collected. The overall HIV-1 incidence rate was 2.54/100PY, but it was 10.0/100PY among male IDU. HIV was strongly associated with injection history; 38 of 39 seroconverters gave a history of IDU. A near full-length genome of HIV-1 was recovered by PCR amplification and sequenced from peripheral mononuclear cell extracted DNA of 38 seroconverters. Phylogenetic analysis revealed that 33 (86.8%) were CRF01_AE and 5 (13.2%) were CRF01_AE/B recombinants. These recombinants had different structure but shared some common breakpoints, indicating an ongoing recombination process. Recombinant infection increased with year of sampling (0 to 57.1%). The molecular epidemiology of HIV-1 among drug users in northern Thailand has thus entered a new era. CRF01_AE remains predominant while pure subtype B is becoming rare, and now a substantial component of the epidemic. These findings support the need for CRF01_AE and subtype B components in clade-matched vaccine strategies for Thai phase III trials. Ongoing molecular surveillance of circulating HIV-1 strains is imperative for the evaluation of HIV vaccine efficacy.

Original languageEnglish (US)
Pages (from-to)465-475
Number of pages11
JournalAIDS research and human retroviruses
Issue number5
StatePublished - May 2004

ASJC Scopus subject areas

  • Immunology
  • Virology
  • Infectious Diseases


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