Analysis of prevalence of HIV-1 drug resistance in primary infections in the United Kingdom

Objectives To identify changes since 1994 in the prevalence of resistance to anti-HIV drugs in primary HIV-1 infections in the United Kingdom. Design Retrospective and prospective assessment of viruses obtained from people recently infected with HIV. Setting Multiple centres (patients enrolled in the UK register of seroconverters) and a single large HIV clinic (active case ascertainment). Participants 69 patients infected with HN between June 1994 and August 2000. Main outcome measures Prevalence of key mutations associated with drug resistance in the reverse transcriptase and protease genes of HIV-1, by year of infection. Results Between June 1994 and August 2000, 10 (14%) of 69 newly infected patients had one or more key HIV-1 mutations associated with drug resistance. The risk of being infected with drug resistant virus increased over time (adjusted relative risk per year 1.74 (95% confidence interval 0.93 to 3.27), P = 0.06). The estimated prevalence of drug resistance in those infected in 2000 was 27% (12% to 48%). Conclusions Transmission of drug resistant HIV-1 in the United Kingdom seems to be increasing. New approaches to encourage safer sexual behaviour in all sectors of the population are urgently needed.