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SARS-CoV-2 variant clades continue to circumvent antibody responses elicited by vaccination or infection. Current parenteral vaccination strategies reduce illness and hospitalization, yet do not significantly protect against infection by the more recent variants. It is thought that mucosal vaccination strategies may better protect against infection by inducing immunity at the sites of infection, blocking viral transmission more effectively, and significantly inhibiting the evolution of new variants of concern (VOCs). In this study, we evaluated the immunogenicity and efficacy of a mucosally-delivered, non-replicating, adenovirus type 5-vectored vaccine that expresses the spike (S) gene of Wuhan (rAd5-S-Wuhan), delta (rAd5-S-delta), or omicron (rAd5-S-omicron) SARS-CoV-2 VOCs. Hamsters were immunized with these vaccines intranasally prior to challenge with omicron or delta variants. Additionally, one group was vaccinated by oral gavage with rAd5-S-Wuhan prior to challenge with the delta variant. Both intranasal and oral administration of rAd5-S-Wuhan generated cross-reactive serum IgG and mucosal IgA to all variant spike and RBD proteins tested. rAd5-S-omicron and rAd5-S-delta additionally elicited cross-reactive antibodies, though rAd5-S-omicron had significantly lower binding antibody levels except against its matched antigens. Two weeks after the final vaccination, hamsters were challenged with a SARS-CoV-2 variant; omicron or delta. Whether matched to the challenge or with rAd5-S-Wuhan, all vaccines protected hamsters from weight loss and lung pathology caused by challenge and significantly reduced viral shedding compared to placebo. Vaccination with rAd5-S-Wuhan provided significant protection, although there was an improved reduction in shedding and disease pathology in groups protected by the matched VOC vaccines. Nevertheless, Wuhan-based vaccination elicited the most cross-reactive antibody responses generally. Overall, heterologous vaccination via mucosal routes may be advantageous for second-generation vaccines.

As new SARS-CoV-2 variants continue to emerge, it is important to evaluate the potency of antiviral drugs to support their continued use. Remdesivir (RDV; VEKLURY®) an approved antiviral treatment for COVID-19, and obeldesivir (ODV) are inhibitors of the SARS-CoV-2 RNA-dependent RNA polymerase Nsp12. Here we show these two compounds retain antiviral activity against the Omicron variants BA.2.86, BF.7, BQ.1, CH.1.1, EG.1.2, EG.5.1, EG.5.1.4, FL.22, HK.3, HV.1, JN.1, JN.1.7, JN.1.18, KP.2, KP.3, LB.1, XBB.1.5, XBB.1.5.72, XBB.1.16, XBB.2.3.2, XBC.1.6, and XBF when compared with reference strains. Genomic analysis identified 29 Nsp12 polymorphisms in these and previous Omicron variants. Phenotypic analysis of these polymorphisms confirmed no impact on the antiviral activity of RDV or ODV and suggests Omicron variants containing these Nsp12 polymorphisms remain susceptible to both compounds. These data support the continued use of RDV in the context of circulating SARS-CoV-2 variants and the development of ODV as an antiviral therapeutic.

With the ongoing emergence of SARS-CoV-2 variants, continued surveillance of antiviral susceptibility remains critical for detecting resistance that could compromise treatment efficacy. This study evaluated the activity of 2 SARS-CoV-2 RNA-dependent RNA polymerase (Nsp12) inhibitors against emerging Omicron variants: remdesivir (RDV), an approved antiviral for the treatment of COVID-19, and obeldesivir (ODV), an oral prodrug that shares the same parent nucleoside as RDV. Both RDV and ODV were shown to retain antiviral activity against the Omicron subvariants BA.2.86.1, JN.1.7, KP.2, KP.3.1.1, KP.3.3, LP.8.1, NB.1.8.1, XBB.2, XEC, and XFG compared with wild-type reference strains. Only 1 new lineage-defining Nsp12 substitution, D284Y (detected in NB.1.8.1), was observed. Phenotypic analysis demonstrated that a replicon containing this substitution remained susceptible to both RDV and ODV. These findings are consistent with previous studies showing that RDV and ODV retain potent activity against previously identified Omicron variants, support the continued clinical use of RDV against circulating SARS-CoV-2 variants, and reinforce the potential of ODV as an oral antiviral therapeutic.

ObjectivesThe HIV epidemic in India is concentrated in key populations such as people who inject drugs (PWID). New HIV infections are high among young PWID (≤30 years of age), who are hard to engage in services. We assessed perspectives of young PWID to guide development of youth-specific services.SettingWe conducted focus group discussions (FGDs) with PWID and staff at venues offering services to PWID in three Indian cities representing historical and emerging drug use epidemics.ParticipantsPWID were eligible to participate if they were between 18 and 35 years, had initiated injection as adolescents or young adults and knew adolescent PWID in their networks. 43 PWID (81% male, 19% female) and 10 staff members participated in FGDs. A semistructured interview guide was used to elicit participants’ narratives on injection initiation experiences, barriers to seeking harm reduction services, service delivery gaps and recommendations to promote engagement. Thematic analysis was used to develop an explanatory model for service engagement in each temporal stage across the injection continuum.ResultsInjection initiation followed non-injection opioid dependence. Lack of services for non-injection opioid dependence was a key gap in the preinjection initiation phase. Lack of knowledge and reliance on informal sources for injecting equipment were key reasons for non-engagement in the peri-injection phase. Additionally, low-risk perception resulted in low motivation to seek services. Psychosocial and structural factors shaped engagement after established injection. Housing and food insecurity, and stigma disproportionately affected female PWID while lack of confidential adolescent friendly services impeded engagement by adolescent PWID.ConclusionsDevelopment of youth-specific services for young PWID in India will need to address unique vulnerabilities and service gaps along each stage of the injection continuum. Scaling-up of tailored services is needed for young female PWID and adolescents, including interventions that prevent injection initiation and provision of confidential harm reduction services.

Background The COVID-19 pandemic intensified existing health and social inequities, disproportionately impacting rural and under-resourced urban communities. Community-led coalitions that leverage the experiences and strengths of diverse stakeholders can play a crucial role in addressing these disparities. Methods The Communities Organizing to Promote Equity (COPE) project, implemented across 20 Kansas counties, utilized community coalitions known as Local Health Equity Action Teams (LHEATs) as the primary intervention strategy. Comprising community residents, social service representatives, and community health workers (CHWs), LHEATs identified and prioritized local inequities to guide their activities. To examine the development and implementation of LHEATs and to identify factors influencing their effectiveness, we conducted a mixed-methods study. Results Between March and September 2022, 216 members completed surveys that captured demographics, social identities, and participation motivations. Semi-structured interviews ( N  = 117) were conducted between August 2022 and September 2023, guided by the Consolidated Framework for Implementation Research. Most (82.4%) identified as female, with over half participating due to job-related roles. Members reported diverse social identities and a shared commitment to their communities. Thematic analysis highlighted contributors to LHEAT effectiveness, including involving individuals with firsthand experience of inequities, the involvement of individuals connected to local services, and the presence of CHWs with dedicated, paid time. CHWs played a key role in recruiting and retaining LHEAT members with lived experience. Participants emphasized the importance of strong academic support, organized meetings, inclusive dialogue, and shared decision-making. Conclusions Findings underscore the need for structured support, inclusive leadership, and clearly defined roles to sustain effective, community-driven responses to health inequities. This model holds promise for large-scale, locally driven change with meaningful community engagement and sustained outcomes.

Cognitive decline is a common symptom in multiple sclerosis patients, with profound effects on the quality of life. A nonhuman primate model of multiple sclerosis would be best suited to test the effects of demyelination on complex cognitive functions such as learning and reasoning. Cuprizone has been shown to reliably induce brain demyelination in mice. To establish a nonhuman primate model of multiple sclerosis, young adult cynomolgus monkeys were administered cuprizone per os as a dietary supplement. The subjects received increasing cuprizone doses (0.3–3% of diet) for up to 18 weeks. Magnetic resonance imaging and immunohistological analyses did not reveal demyelination in these monkeys.

BackgroundTAF resistance has not been detected after up to three years of treatment in CHB patients. Here, we report results from annual resistance surveillance from years 3 through 8 of TAF treatment.MethodsTwo randomized, double-blind (DB), active-controlled trials to evaluate TAF treatment of hepatitis e antigen (HBeAg)-negative and HBeAg-positive participants with CHB were conducted over 8 years (384 weeks). Sequence analysis of the pol/RT region was attempted for any participant who experienced a viral breakthrough, viral blip, or persistent viremia with HBV DNA ≥69 IU/mL at annual intervals and for any participant who discontinued the study drug with HBV DNA ≥69 IU/mL. Participants that developed substitutions at conserved pol/RT sites or at polymorphic residues (if observed in ≥2 participants within the study) were also phenotyped against TAF.ResultsOut of 1298 participants, the percentage of participants who qualified for resistance analysis annually from Week 144 to Week 384 remained low (range 1.7 – 8.4%). Among those qualifying for sequencing, the proportions with persistent viremia progressively declined with time, with only 3 participants being persistently viremic by Year 8. The viral load of these 3 participants at baseline was >108 log10 IU/mL and declined over time but did not reach 69 IU/mL. During the 5-year open-label period where all participants received TAF, conserved site substitutions in the HBV viral pol/RT were observed in 13 participants.ConclusionsOverall, no resistance to TAF was detected in adult CHB participants with positive or negative HBeAg who received TAF therapy for up to 8 years.

Respiratory syncytial virus (RSV) is a significant cause of morbidity and mortality in high-risk populations. Although prophylactic options are available, there are no effective oral therapeutics for RSV infection. Obeldesivir (ODV) is an orally bioavailable prodrug of the nucleoside analog GS-441524, which is converted intracellularly to its active nucleoside triphosphate and inhibits the RSV RNA polymerase. Here we report the potent antiviral activity of ODV against geographically and temporally diverse RSV A and B clinical isolates (EC 50 : 0.20–0.66 μM). Resistance selection studies with ODV and GS-441524 against RSV identify a single amino acid substitution, I777L, in the L polymerase with reduced susceptibility (3.3-3.8-fold) to ODV and GS-441524, indicating a high barrier for resistance development. In an African green monkey RSV infection model, once-daily oral ODV doses of 30 or 90 mg/kg initiated ~24 hours post-infection significantly reduces log 10 viral RNA copies/mL × day area under the curve by 69–92% in the upper and lower respiratory tracts. Together, these preclinical data support the clinical evaluation of ODV for the treatment of RSV infection. In this work, authors show that the nucleoside prodrug obeldesivir has potent antiviral activity across respiratory syncytial virus (RSV) clinical isolates with a high resistance barrier. Once-daily obeldesivir treatment was efficacious against RSV in a non-human primate model.