BACKGROUND:

Transmitted HIV-1 drug resistance (TDR) is an ongoing public health problem, representing 10-20% of new HIV infections in many geographic areas. TDR usually arises from two main sources: individuals on antiretroviral therapy (ART) who are failing to achieve virologic suppression, and individuals who acquired TDR and transmit it while still ART-naïve. TDR rates can be impacted when novel antiretroviral medications are introduced that allow for greater virologic suppression of source patients. Although several new HIV medications were introduced starting in late 2007, including raltegravir, maraviroc, and etravirine, it is not known whether the prevalence of TDR was subsequently affected in 2008-2009.

METHODOLOGY/PRINCIPAL FINDINGS:

We performed population sequence genotyping on individuals who were diagnosed with acute or early HIV (<6 months duration) and who enrolled in the Options Project, a prospective cohort, between 2002 and 2009. We used logistic regression to compare the odds of acquiring drug-resistant HIV before versus after the arrival of new ART (2005-2007 vs. 2008-2009). From 2003-2007, TDR rose from 7% to 24%. Prevalence of TDR was then 15% in 2008 and in 2009. While the odds of acquiring TDR were lower in 2008-2009 compared to 2005-2007, this was not statistically significant (odds ratio 0.65, 95% CI 0.31-1.38; p = 0.27).

CONCLUSIONS:

Our study suggests that transmitted drug resistance rose from 2003-2007, but this upward trend did not continue in 2008 and 2009. Nevertheless, the TDR prevalence in 2008-2009 remained substantial, emphasizing that improved management strategies for drug-resistant HIV are needed if TDR is to be further reduced. Continued surveillance for TDR will be important in understanding the full impact of new antiretroviral medications.