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Background:  Most existing data examine transmitted resistance among patients who are identified as acutely infected based on clinical suspicion. North Carolina recently introduced a model program (STAT) for all state-funded HIV testing in which all HIV EIA (^–) specimens are tested for acute HIV using RNA, and all HIV EIA (⁺) specimens are tested for “recent” infection using a detuned HIV EIA. We compared this novel VCT-based surveillance with more traditional, clinically driven acute HIV surveillance in the same geographic area.

Methods:  Two groups of patients had genotypic resistance testing:  26 symptomatic patients referred from across North Carolina to the Duke–UNC–Emory Acute HIV Consortium diagnosed clinically between 1998 and 2004; 76 patients requesting publicly funded HIV VCT from November 2002 to April 2004, with no previous HIV⁺ test result. Both “acute” (HIV RNA⁺/antibody^– at testing; n = 19) or “recently acute” (HIV antibody⁺ at testing but negative on a detuned HIV EIA; n = 57) specimens were sequenced. Bulk sequencing of RT and protease was done using Genosure or Trugene. Only major resistance mutations were included in analyses, as defined by 2000 IAS-USA guidelines.

Results:  Overall, major resistance mutations were detected in 11 (10.8%; 95% CI 5.5 to 18.5%) of 102 patients in North Carolina, coding resistance to nucleoside reverse transcriptase inhibitors (NRTI) (3, 2.9%), non-NRTI (NNRTI) (6, 5.9%), protease inhibitors (PI) (5, 4.9%), or multiple classes (3, 2.9%). Overall frequencies of mutations were similar among “acute” (4 of 45, 8.9%) and “recent” (7 of 57, 12.3%) infections. Prevalence estimates for the VCT-based population (9 of 76 or 11.8%, 95% CI 5.6 to 21.3%) were more precise than for the referral population (2 of 26 or 7.7%, 95% CI 0.9 to 25.1%). Major PI mutations and multi-class resistance were only detected in recent infections from the STAT VCT population. 

Conclusions:  Observed rates of transmitted resistance in North Carolina (around 10%) and the detection of multi-drug-resistance transmission argue for an important role of HIV genotypic screening in the evaluation of newly or recently HIV-infected patients in the state and underscore the public health importance of monitoring systems. VCT programs incorporating active laboratory-based surveillance for early HIV infection can more reliably identify patterns of transmitted resistance in defined geographic areas than collection of data on patients with clinically suspected acute HIV. These data provide North Carolina with a baseline for prospective monitoring of trends in transmission of ARV resistance over time.

Keywords: resistance; acute HIV infection; HIV diagnosis