Evidence of a decline in transmitted HIV-1 drug resistance in the United Kingdom

Abstract
To examine recent trends in transmitted drug resistance (TDR) in the United Kingdom. Analysis of results of genotypic resistance tests reported to the UK HIV Drug Resistance Database, which includes virtually all tests conducted as part of routine clinical care nationally. Resistance was based on major mutations as defined in the 2005 International AIDS Society-USA guidelines. Analysis was restricted to persons who were antiretroviral treatment-naive at the time of sampling, and a test defined as relating to recent infection if the patient was co-enrolled in the UK Register of HIV Seroconverters and the sample taken within 18 months of a negative HIV antibody test. A total of 4454 samples from treatment-naive patients between 1996 and 2004 were analysed, including 316 from patients recently infected at the time of the resistance test. After an initial rise, TDR declined from a peak of around 14% in 2001–2002 to around 8% by the end of 2004 (Ptrend Conclusions: This is the first clear evidence of a decrease in TDR at national level. The wider use of regimens that suppress viral concentration to below infectious levels is one of several plausible explanations for this finding.