During April-August 2020, a preemptive testing strategy combined with accessible isolation and symptom screening among people experiencing homelessness in congregant living settings in San Diego contributed to a low incidence proportion of COVID-19: 0.9%. Proactively addressing challenges specific to a vulnerable population may significantly prevent spread and community outbreaks.

Hepatitis C virus (HCV) is a major cause of cirrhosis, liver cancer, and mortality in the United States. We assessed the effectiveness of decentralized HCV treatment delivered by nurse practitioners (NPs), primary care physicians (PMDs), or an infectious disease physician (ID MD) using direct‐acting antivirals in a Federally Qualified Health Center (FQHC) in urban San Diego, CA. We conducted a cross‐sectional analysis of 1,261 patients who received treatment from six NPs, 10 PMDs, and one ID MD practicing in 10 clinics between January 2014 and January 2020. Care was delivered based on the Extension for Community Healthcare Outcomes (Project ECHO) model with one hub and nine spokes. HCV was deemed cured if a patient had a sustained virologic response (SVR) after 12 weeks of treatment (SVR12). We evaluated differences in the prevalence of cure between provider types and hub or spoke status using Poisson regression. Patients were 34% Latino, 16% black, 63% were aged >50 years, and 59% were homeless; 53% had advanced fibrosis, 69% had genotype 1, and 5% were coinfected with human immunodeficiency virus. A total of 943 patients achieved SVR12 (96% per protocol and 73% intention to treat). Even after adjustment for demographics, resources, and disease characteristics, the prevalence of cure did not differ between the ID MD and PMDs (prevalence ratio [PR], 1.00; 95% confidence interval [CI], 0.95‐1.04) or NPs (PR, 1.01; 95% CI, 0.96‐1.05). Similarly, there were no differences between the hub and spokes (PR, 1.01; 95% CI, 0.98‐1.04). Conclusion: Among a low‐income and majority homeless cohort of patients at urban FQHC clinics, HCV treatment administered by nonspecialist providers was not inferior to that provided by a specialist.

Background Consistent with young adults’ penchant for digital communication, young adults living with HIV use digital communication media to seek out health information. Understanding the types of health information sought online and the characteristics of these information-seeking young adults is vital when designing digital health interventions for them. Objective This study aims to describe characteristics of young adults living with HIV who seek health information through the internet. Results will be relevant to digital health interventions and patient education. Methods Young adults with HIV (aged 18-34 years) self-reported internet use during an evaluation of digital HIV care interventions across 10 demonstration projects in the United States (N=716). Lasso (least absolute shrinkage and selection operator) models were used to select characteristics that predicted whether participants reported seeking general health and sexual and reproductive health (SRH) information on the internet during the past 6 months. Results Almost a third (211/716, 29.5%) and a fifth (155/716, 21.6%) of participants reported searching for general health and SRH information, respectively; 26.7% (36/135) of transgender young adults with HIV searched for gender-affirming care topics. Areas under the curve (>0.70) indicated success in building models to predict internet health information seeking. Consistent with prior studies, higher education and income predicted health information seeking. Higher self-reported antiretroviral therapy adherence, substance use, and not reporting transgender gender identity also predicted health information seeking. Reporting a sexual orientation other than gay, lesbian, bisexual, or straight predicted SRH information seeking. Conclusions Young adults living with HIV commonly seek both general health and SRH information online, particularly those exploring their sexual identity. Providers should discuss the most commonly sought SRH topics and the use of digital technology and be open to discussing information found online to better assist young adults with HIV in finding accurate information. Characteristics associated with health information–seeking behavior may also be used to develop and tailor digital health interventions for these young adults.

e14588 Background: The PD-L1 IHC 28-8 pharmDx assay has been developed for use in detection of PD-L1 protein in formalin-fixed, paraffin-embedded (FFPE) non-squamous NSCLC and melanoma tissues for associated treatment effect with nivolumab. Validation of the assay for measuring PD-L1 expression level in human squamous cell carcinoma of the head and neck (SCCHN) FFPE sections has been conducted and results are described. Methods: Visualization of the PD-L1 IHC 28-8 pharmDx assay is based on the EnVision FLEX IHC technology. As described in the Instructions For Use, antigen retrieval was performed using the Dako PT Link, and the automated staining was conducted with Autostainer Link 48. The assay performance was validated on commercially procured FFPE SCCHN specimens. Results: Assessment of assay sensitivity to PD-L1 expression was measured on 236 unique specimens originating from squamous cell carcinoma of the tongue, tonsil, nasopharynx, oropharynx, hypopharynx, and larynx. The study demonstrated PD-L1 positive staining across a range of 0-95% positive tumor cells and 0 to 3+ staining intensity. Among these tested specimens, 44% of specimens had PD-L1 expression levels ≥1%. Assay robustness was validated by assessing critical parameters such as target retrieval solution pH, target retrieval solution temperature, target retrieval time, and cut section thickness. Assay reproducibility was evaluated in a study at three external sites. Reproducibility of intra-site, inter-day, and inter-site agreement was assessed in addition to inter- and intra-observer agreement. Assay robustness and reproducibility demonstrated agreement estimates above 85% with values for lower bound 95% confidence intervals calculated above 85%. Conclusions: These studies demonstrate that the PD-L1 IHC 28-8 pharmDx assay is reproducible and robust when used for automated detection of PD-L1 protein in FFPE human SCCHN specimens using Autostainer Link 48.

Background Monoclonal antibody (mAb) treatment for COVID-19 is associated with improved clinical outcomes. However, there is limited information regarding the impact of treatment on symptoms and the prevalence of post-COVID Conditions (PCC). Understanding of the association between time to mAb infusion and the development of PCC is also limited. Methods This longitudinal study was conducted among patients with COVID-19 who received mAb infusions at a Federally Qualified Health Center in San Diego, CA. A series of telephone interviews were conducted at baseline and follow-up (14 days and 28+ days). A comprehensive symptom inventory was completed and physical and mental health status were measured using PROMIS-29 and PHQ-2. Pearson’s Chi-squared tests and independent two-sample t-tests were performed to test for association between time to mAb infusion and outcomes at follow-up. A Poisson regression model was used to analyze whether time to mAb infusion predicts risk of developing PCC. Results Participants (N = 411) were 53% female, ranged in age from 16 to 92 years (mean 50), and a majority (56%) were Latino/Hispanic. Cross-sectional findings revealed a high symptom burden at baseline (70% of patients had cough, 50% had fever, and 44% had headache). The prevalence of many symptoms decreased substantially by the final follow-up survey (29% of patients had cough, 3% had fever, and 28% had headache). Longitudinal findings indicated that 10 symptoms decreased in prevalence from baseline to final follow-up, 2 remained the same, and 14 increased. The severity of symptoms and most patient-reported physical and mental health measure scores decreased over time. The prevalence of PCC was 69% when PCC was defined as ≥ 1 symptom at final follow-up. Time to mAb infusion was not significantly associated with any outcome at follow-up. Time to infusion was not associated with PCC status at final follow-up in the crude or adjusted Poisson regression models. Conclusions The prevalence of PCC was high among this patient population following COVID-19 mAb treatment. Time to mAb infusion did not predict the development of PCC. Further research in these areas is essential to answer urgent clinical questions about effective treatments of COVID-19.