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Background: The safety and efficacy of the AZD1222 (ChAdOx1 nCoV-19) vaccine in a large, diverse population at increased risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the United States, Chile, and Peru has not been known., Methods: In this ongoing, double-blind, randomized, placebo-controlled, phase 3 clinical trial, we investigated the safety, vaccine efficacy, and immunogenicity of two doses of AZD1222 as compared with placebo in preventing the onset of symptomatic and severe coronavirus disease 2019 (Covid-19) 15 days or more after the second dose in adults, including older adults, in the United States, Chile, and Peru., Results: A total of 32,451 participants underwent randomization, in a 2:1 ratio, to receive AZD1222 (21,635 participants) or placebo (10,816 participants). AZD1222 was safe, with low incidences of serious and medically attended adverse events and adverse events of special interest; the incidences were similar to those observed in the placebo group. Solicited local and systemic reactions were generally mild or moderate in both groups. Overall estimated vaccine efficacy was 74.0% (95% confidence interval [CI], 65.3 to 80.5; P<0.001) and estimated vaccine efficacy was 83.5% (95% CI, 54.2 to 94.1) in participants 65 years of age or older. High vaccine efficacy was consistent across a range of demographic subgroups. In the fully vaccinated analysis subgroup, no severe or critical symptomatic Covid-19 cases were observed among the 17,662 participants in the AZD1222 group; 8 cases were noted among the 8550 participants in the placebo group (<0.1%). The estimated vaccine efficacy for preventing SARS-CoV-2 infection (nucleocapsid antibody seroconversion) was 64.3% (95% CI, 56.1 to 71.0; P<0.001). SARS-CoV-2 spike protein binding and neutralizing antibodies increased after the first dose and increased further when measured 28 days after the second dose., Conclusions: AZD1222 was safe and efficacious in preventing symptomatic and severe Covid-19 across diverse populations that included older adults. (Funded by AstraZeneca and others; ClinicalTrials.gov number, NCT04516746.)., (Copyright © 2021 Massachusetts Medical Society.)

HIV Vaccine Trials Network (HVTN) 505 was a phase 2b efficacy trial of a DNA/recombinant adenovirus 5 (rAd5) HIV vaccine regimen. Although the trial was stopped early for lack of overall efficacy, later correlates of risk and sieve analyses generated the hypothesis that the DNA/rAd5 vaccine regimen protected some vaccinees from HIV infection yet enhanced HIV infection risk for others. Here, we assessed whether and how host Fc gamma receptor (FcγR) genetic variations influenced the DNA/rAd5 vaccine regimen's effect on HIV infection risk. We found that vaccine receipt significantly increased HIV acquisition compared with placebo receipt among participants carrying the FCGR2C-TATA haplotype (comprising minor alleles of four FCGR2C single-nucleotide polymorphism [SNP] sites) (hazard ratio [HR] = 9.79, P  = 0.035) but not among participants without the haplotype (HR = 0.86, P  = 0.67); the interaction of vaccine and haplotype effect was significant ( P  = 0.034). Similarly, vaccine receipt increased HIV acquisition compared with placebo receipt among participants carrying the FCGR3B-AGA haplotype (comprising minor alleles of the 3 FCGR3B SNPs) (HR = 2.78, P  = 0.058) but not among participants without the haplotype (HR = 0.73, P  = 0.44); again, the interaction of vaccine and haplotype was significant ( P = 0.047). The FCGR3B-AGA haplotype also influenced whether a combined Env-specific CD8 + T-cell polyfunctionality score and IgG response correlated significantly with HIV risk; an FCGR2A SNP and two FCGR2B SNPs influenced whether anti-gp140 antibody-dependent cellular phagocytosis correlated significantly with HIV risk. These results provide further evidence that Fc gamma receptor genetic variations may modulate HIV vaccine effects and immune function after HIV vaccination. IMPORTANCE By analyzing data from the HVTN 505 efficacy trial of a DNA/recombinant adenovirus 5 (rAd5) vaccine regimen, we found that host genetics, specifically Fc gamma receptor genetic variations, influenced whether receiving the DNA/rAd5 regimen was beneficial, neutral, or detrimental to an individual with respect to HIV-1 acquisition risk. Moreover, Fc gamma receptor genetic variations influenced immune responses to the DNA/rAd5 vaccine regimen. Thus, Fc gamma receptor genetic variations should be considered in the analysis of future HIV vaccine trials and the development of HIV vaccines., (Copyright © 2019 American Society for Microbiology.)

Human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) has high biomedical efficacy; however, awareness, access, uptake, and persistence on therapy remain low among black men who have sex with men (BMSM), who are at highest risk of HIV in the United States. To date, discussions of "PrEP failure" have focused on one typology: rare, documented HIV acquisitions among PrEP users with adequate serum drug levels (ie, biomedical failure). In our cohort of HIV-negative young BMSM in Atlanta, Georgia, we continue to observe a high HIV incidence (6.2% annually at interim analysis) despite access to free PrEP services. Among 14 seroconversions, all were offered PrEP before acquiring HIV. Among these participants, we identified 4 additional typologies of PrEP failure that expand beyond biomedical failure: low PrEP adherence, PrEP discontinuation, PrEP contemplation without initiation, and PrEP refusal. We describe the 5 typologies and suggest interventions to improve PrEP effectiveness among those at highest risk.

Objectives: To evaluate the safety and efficacy of the novel tenofovir prodrug, tenofovir alafenamide (TAF), as part of a single-tablet regimen (STR) for the initial treatment of HIV-1 infection., Design: Phase 2, randomized, double-blind, double-dummy, multicenter, active-controlled study., Methods: Antiretroviral naive adults with HIV-1 RNA ≥5000 copies per milliliter and a CD4 count ≥50 cells per microliter were randomized 2:1 to receive an STR of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) or elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (E/C/F/TDF), plus placebo for 48 weeks., Results: Patients on both E/C/F/TAF (n = 112) and E/C/F/TDF (n = 58) had high rates of virologic suppression (<50 HIV copies per milliliter) at week 24 (86.6%; 89.7%) and at week 48 (88.4%; 87.9%), and had similar improvements in CD4 at week 48 (177; 204), respectively. Both treatments were well tolerated, and most adverse events were self-limiting and of mild to moderate severity. Compared with patients on E/C/F/TDF, patients on E/C/F/TAF had smaller reductions in estimated creatinine clearance (-5.5 vs. -10.1 mL/min, P = 0.041), significantly less renal tubular proteinuria, and smaller changes in bone mineral density for hip (-0.62% vs. -2.39%, P < 0.001) and spine (-1.00% vs. -3.37%, P < 0.001). Patients on E/C/F/TAF had higher increases in total cholesterol, low-density lipoprotein, and high-density lipoprotein, but the total cholesterol/high-density lipoprotein ratio was unchanged for both., Conclusions: Treatment-naive patients given the STR that contained either TAF or TDF achieved a high rate of virologic success. Compared with those receiving TDF, patients on E/C/F/TAF experienced significantly smaller changes in estimated creatinine clearance, renal tubular proteinuria, and bone mineral density.

Background: Pill burden, dosing frequency, and concerns about safety and tolerability are important obstacles to maintaining adequate medication adherence. Raltegravir (RAL) is indicated for twice-daily dosing and when taken with emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF), it becomes a twice-daily multiple-tablet regimen. Elvitegravir (EVG)/cobicistat (COBI)/FTC/TDF, STB, is the first approved once-a-day integrase strand transfer inhibitor (INSTI) containing single-tablet regimen that combines EVG, an INSTI, and COBI, a novel pharmacoenhancer, with the preferred nucleos(t)ide backbone of FTC/TDF., Methods: This was a 48-week prospective, single-arm open-label study of the switch to STB in virologically sup-pressed HIV-1-infected adult patients on FTC/TDF and twice-daily RAL for at least 6 months. Objectives were to evaluate the tolerability and safety of a regimen simplification to once-a-day STB, while maintaining viral suppression through 48 weeks., Results: Forty-eight individuals in the United States were enrolled. The median age was 44 years, 96% were male, and 83% were White. The median time on RAL + FTC/TDF treatment prior to enrollment was 34 months. Ninety-six percent of participants cited regimen simplification as the reason to enroll in the switch study. At base-line, the median CD4 count was 714 cell/µL and estimated glomerular filtration rate (eGFR) was 105 mL/min. At week 48, all assessed study participants remained viro-logically suppressed to the lower limit of quantification (HIV-1 RNA<50 copies/mL) and maintained high CD4 cell count (median, 751 cells/mL) and stable eGFR (median, 100.5 mL/min). STB was well tolerated with no discontinuations, no study drug-related serious adverse events, and no study drug-related grade 3/4 adverse events., Conclusions: All participants switching to 1 tablet once-a-day STB from a twice-daily RAL + FTC/TDF regimen remained virologically suppressed. STB was well tolerated. Switching to STB may be a viable option for virologically suppressed patients wanting to simplify from a twice-daily RAL-containing regimen.