K103N-containing variants persist in some women and infants for 1 year or more after the administration of SD-NVP. Sensitive resistance assays may provide new insight into the impact of antiretroviral drug exposure on HIV-1 evolution.

K103N-containing human immunodeficiency virus (HIV)-1 variants are selected in some women who receive single-dose (SD) nevirapine (NVP) for prevention of HIV-1 mother-infant transmission. We examined the persistence of K103N in women who received SD NVP prophylaxis. K103N was detected using the LigAmp assay (assay cutoff, 0.5% K103N). K103N was detected at 6-8 weeks in 60 (41.7%) of 144 women. Fading (lack of detection) of K103N was documented in 16 women by 2 years, 43 women by 3 years, and 55 women by 4 and 5 years. Slower fading was independently associated with HIV-1 subtype (D>A) and higher pre-NVP viral load.

After administration of single-dose NVP, K103N was detected more frequently and at higher levels in women with subtypes C and D than A. Further studies are needed to evaluate the clinical significance of NVP-resistant variants in this setting.

The US Food and Drug Administration-cleared ViroSeq HIV-1 Genotyping System (ViroSeq) and other population sequencing-based human immunodeficiency virus type 1 (HIV-1) genotyping methods detect antiretroviral drug resistance mutations present in the major viral population of a test sample. These assays also detect some mutations in viral variants that are present as mixtures. We compared detection of the K103N nevirapine resistance mutation using The US Food and Drug Administration-cleared ViroSeq HIV-1 Genotyping System (ViroSeq) and other population sequencing-based genotyping methods detect mutations present in the major viral population in a test sample. These assays also detect some mutations that are present at lower levels. Using recombinant viral stocks, we previously demonstrated that ViroSeq reliably detects drug resistance mutations present in 40% of the viral population in samples with viral loads from 2000 to 5000 copies/ml 1 , lower level mixtures were not evaluated in that study. In another study, ViroSeq detected the K103N mutation in a recombinant human immunodeficiency virus type 1 (HIV-1) strain at a level of 10%. 2HIV-1 variants with the K103N mutation are often selected in women who receive a single dose of the antiretroviral drug nevirapine for prevention of HIV-1 motherto-child transmission. 3,4 We evaluated the sensitivity of ViroSeq for detection of K103N in 305 clinical plasma samples collected from African women 6 to 8 weeks after single dose nevirapine administration. Samples were collected from women in the HIV Network for Prevention Trial (HIVNET) 012 trial 5,6 (Ugandan women, 146 subtype A samples and 95 subtype D samples) and the Nevirapine-

Latinos in the U.S. are disproportionately affected by HIV and are at risk for late presentation to care. Between June 2011 and January 2012, we conducted a cross-sectional survey of 209 Baltimore Latinos at community-based venues to evaluate the feasibility of using communication technology (ICT)-based interventions to improve access to HIV testing and education within the Spanish-speaking community in Baltimore. Participants had a median age of 33 years (IQR 28-42), 51.7% were male, and 95.7% were foreign-born. Approximately two-thirds (63.2%) had been in the U.S. less than 10 years and 70.1% had been previously tested for HIV. Cell phone (92.3%) and text messaging (74.2%) was used more than Internet (52.2%) or e-mail (42.8%) (p<0.01). In multivariate analysis, older age and lower education were associated with less utilization of Internet, e-mail and text messaging, but not cell phones. Interest was high for receiving health education (73.1%), HIV education (70.2%), and test results (68.8%) via text messaging. Innovative cell phone-based communication interventions have the potential to link Latino migrants to HIV prevention, testing and treatment services.

Single dose (SD) nevirapine (NVP) significantly reduces HIV mother-to-child transmission. We analyzed NVP resistance after SD NVP in 57 previously SD NVP-naїve women, 34 SD NVP-experienced women, and 17 HIV-infected infants. The proportion of women with resistance, the types of mutations detected, and the frequency and level of K103N were similar in the two groups of women at 6 weeks and 6 months post-partum. NVP resistance was detected in a similar proportion of infants born to SD NVP-naїve versus SD NVP-experienced women. Repeated use of SD NVP to prevent HIV transmission does not appear to influence NVP resistance.

Sequence variation in the gag p6 region in subtype B HIV-1 has been associated with changes in viral replication capacity and antiretroviral drug susceptibility. We examined sequence variation in the HIV-1 gag p6 region using plasma samples from 22 individuals with non-subtype B HIV-1 infection [subtypes A, C, D, F, and G, and circulating recombinant forms (CRFs) CRF01-AE and CRF02_AG]. An additional 105 gag sequences from the Los Alamos National Laboratory database were also analyzed. Extensive length variation was observed in the p6 gag region. Specific patterns of insertions and deletions were observed in different subtypes and CRFs, and no two subtypes or CRFs had the same general pattern. PTAP duplications were more common in subtype C than other strains (3 of 14 in subtype C vs. 2 of 113 in other strains, p = 0.004), and KQE duplications were seen only in subtype B. Further studies are needed to determine whether such genotypic differences influence viral replication capacity, antiretroviral drug susceptibility, or other phenotypic properties of these strains.

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