High Rates of Missed HIV Testing Among Oral PrEP Users in the United States From 2018-2021: A National Assessment on Compliance With HIV Testing Recommendations of the CDC PrEP Guidelines.

Background: The US Centers for Disease Control and Prevention recommends HIV testing every 3 months in oral PrEP users. We performed a national assessment of HIV testing compliance among oral PrEP users. Methods: We analyzed 408 910 PrEP prescriptions issued to 39 809 PrEP users using a national insurance claims database that contained commercial and Medicaid claims. We identified PrEP use based on pharmacy claims and outpatient diagnostic coding. We evaluated the percentage of PrEP prescription refills without HIV testing (identified by CPT codes) within the prior 3, 6, and 12 months using time to event methods. We performed subgroup and multivariate analyses by age, gender, race, insurance type, and geography. Results: Of 39 809 persons, 36 197 were commercially insured, 3612 were Medicaid-insured, and 96% identified as male; the median age (interquartile range) was 34 (29-44) years, and the Medicaid-insured PrEP users were 24% Black/African American, 44% White, and 9% Hispanic/Latinx. Within the prior 3, 6, and 12 months, respectively, the percentage of PrEP prescription fills in individuals without HIV Ag/Ab testing was 34.3% (95% CI, 34.2%-34.5%), 23.8% (95% CI, 23.7%-23.9%), and 16.6% (95% CI, 16.4%-16.7%), and the percentage without any type of HIV test was 25.8% (95% CI, 25.6%-25.9%), 14.6% (95% CI, 14.5%-14.7%), and 7.8% (95% CI, 7.7%-7.9%). Conclusions: Approximately 1 in 3 oral PrEP prescriptions were filled in persons who had not received an HIV Ag/Ab test within the prior 3 months, with evidence of health disparities. These findings inform clinical PrEP monitoring efforts and compliance with national HIV testing guidance to monitor PrEP users.

Epidemiology of human immunodeficiency virus (HIV) drug resistance in HIV patients with virologic failure of first-line therapy in the country of Georgia.

Human immunodeficiency virus (HIV) drug resistance is a major threat to the sustained impact of antiretroviral therapy (ART). We studied the epidemiology of drug resistance in the country of Georgia. The study included all adult patients who experienced virologic failure on first line ART and received HIV drug resistance testing between 2005 and 2016. The Stanford HIV Sequence Database was used for interpretation of the resistance data. Patient-level data were extracted from the national AIDS health information system. Of the 447 patients included, 85.5% harbored the subtype A6 virus, 8.0% - subtype B, 2.9% - subtype G, and other subtypes were <1%. The most frequent first-line regimens were Tenofovir/Emtricitabine/Efavirenz (28.4%), Zidovudine/Lamivudine/Efavirenz (28.4%), and Abacavir/Lamivudine/Efavirenz (15.9%). A total of 85.0% of the patients with treatment failure developed at least one drug resistance mutation affecting their susceptibility to ART. The most frequent nucleoside reverse transcriptase inhibitor mutations were M184V (65.3%), K65R (19.7%) and L74V (17.0%). At least three thymidine analogue mutations were detected in 6.3% of the patients. From non-nucleoside reverse transcriptase inhibitor mutations, G190S was shown to be the most prevalent (49.4%), followed by K101E (27.10%) and K103N (24.4%). G190S and K101E were more common in subtype A as compared with non-A viruses (G190S: 54.9% vs 11.3%, P < 0.0001; K101E: 29.8% vs 11.3%, P = 0.005). On the other hand, K103N was more frequent in non-A subtypes (43.4%) compared with subtype A (22.2%), P = 0.0008. A majority of persons failing on ART had HIV drug resistance. Drug resistance patterns may vary by subtype. K65R mutation remains below 20%, but given the high use of Tenofovir in the country, continuing surveillance of drug resistance is needed.

Electric field-induced emission enhancement and modulation in individual CdSe nanowires.

CdSe nanowires show reversible emission intensity enhancements when subjected to electric field strengths ranging from 5 to 22 MV/m. Under alternating positive and negative biases, emission intensity modulation depths of 14 ± 7% are observed. Individual wires are studied by placing them in parallel plate capacitor-like structures and monitoring their emission intensities via single nanostructure microscopy. Observed emission sensitivities are rationalized by the field-induced modulation of carrier detrapping rates from NW defect sites responsible for nonradiative relaxation processes. The exclusion of these states from subsequent photophysics leads to observed photoluminescence quantum yield enhancements. We quantitatively explain the phenomenon by developing a kinetic model to account for field-induced variations of carrier detrapping rates. The observed phenomenon allows direct visualization of trap state behavior in individual CdSe nanowires and represents a first step toward developing new optical techniques that can probe defects in low-dimensional materials.