Abstract

Objectives: We combine laboratory, clinical and sequence-based data to assess the differential uptake of voluntary confidential HIV testing (VCT) according to risk, and explore the occurrence of HIV transmission from individuals with a recently acquired HIV infection, prior to diagnostic opportunity.

Methods: Between 1999-2002, nearly 30,000 anonymous tests for previously undiagnosed HIV infection were conducted among men who have sex with men (MSM) attending 15 sentinel STI clinics in England, Wales and Northern Ireland. Using a serological testing algorithm, undiagnosed HIV-infected men were categorised into those with recent, and non-recent infection. VCT uptake was compared between HIV negative, recently HIV-infected and non-recently HIV-infected men. A phylogenetic analysis of HIV pol sequences from 127 recently HIV-infected MSM was conducted to identify instances where transmission may have occurred before diagnostic opportunity.

Results: HIV negative MSM were more likely to receive VCT at clinic visits compared to undiagnosed HIV-infected MSM (56% (14020/24938) vs. 31% (335/1072), p<0.001). Recently HIV-infected MSM were more likely to receive VCT compared to those with non-recent infections (42% (97/229) vs. 28% (238/844), p<0.001). Twenty-two percent (95/425) of undiagnosed HIV-infected MSM with STIs received VCT. Phylogenetic analysis revealed at least seven transmissions may have been generated by recently HIV-infected MSM: a group that attended STI clinics soon after seroconversion.

Conclusions: The integration of clinical, laboratory and sequence-based data reveals the need for specific targeting of the recently HIV-exposed, and those with STIs, for VCT. However, VCT promotion alone may be limited in its ability to prevent HIV transmission.