Comparison of SARS-CoV-2 Reverse Transcriptase Polymerase Chain Reaction and BinaxNOW Rapid Antigen Tests at a Community Site During an Omicron Surge : A Cross-Sectional Study.

BACKGROUND: SARS-CoV-2 rapid antigen tests are an important public health tool. OBJECTIVE: To evaluate field performance of the BinaxNOW rapid antigen test (Abbott) compared with reverse transcriptase polymerase chain reaction (RT-PCR) for detecting infection with the Omicron variant of SARS-CoV-2. DESIGN: Cross-sectional surveillance study. SETTING: Free, walk-up, outdoor, urban community testing and vaccine site led by Unidos en Salud, serving a predominantly Latinx community highly impacted by COVID-19. PARTICIPANTS: Persons seeking COVID-19 testing in January 2022. MEASUREMENTS: Simultaneous BinaxNOW and RT-PCR from nasal, cheek, and throat swabs, including cycle threshold (Ct) measures; a lower Ct value is a surrogate for higher amounts of virus. RESULTS: Among 731 persons tested with nasal swabs, there were 296 (40.5%) positive results on RT-PCR; 98.9% were the Omicron variant. BinaxNOW detected 95.2% (95% CI, 91% to 98%) of persons who tested positive on RT-PCR with a Ct value below 30, 82.1% (CI, 77% to 87%) of those who tested positive on RT-PCR with a Ct value below 35, and 65.2% (CI, 60% to 71%) of all who were positive on RT-PCR. Among 75 persons with simultaneous nasal and cheek swabs, BinaxNOW using a cheek swab failed to detect 91% (20 of 22) of specimens that were positive on BinaxNOW with a nasal swab. Among persons with simultaneous nasal and throat swabs who were positive on RT-PCR with a Ct value below 30, 42 of 49 (85.7%) were detected by nasal BinaxNOW, 23 of 49 (46.9%) by throat BinaxNOW, and 44 of 49 (89.8%) by either. LIMITATION: Participants were a cross-sectional sample from a community-based sentinel surveillance site, precluding study of viral or symptom dynamics. CONCLUSION: BinaxNOW detected persons with high SARS-CoV-2 levels during the Omicron surge, enabling rapid responses to positive test results. Cheek or throat swabs should not replace nasal swabs. As currently recommended, high-risk persons with an initial negative BinaxNOW result should have repeated testing. PRIMARY FUNDING SOURCE: University of California, San Francisco.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Transmission Dynamics and Immune Responses in a Household of Vaccinated Persons.

While SARS-CoV-2 vaccines prevent severe disease effectively, postvaccination "breakthrough" COVID-19 infections and transmission among vaccinated individuals remain ongoing concerns. We present an in-depth characterization of transmission and immunity among vaccinated individuals in a household, revealing complex dynamics and unappreciated comorbidities, including autoimmunity to type 1 interferon in the presumptive index case.

Estimation of Secondary Household Attack Rates for Emergent Spike L452R Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Variants Detected by Genomic Surveillance at a Community-Based Testing Site in San Francisco.

BACKGROUND: Sequencing of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral genome from patient samples is an important epidemiological tool for monitoring and responding to the pandemic, including the emergence of new mutations in specific communities. METHODS: SARS-CoV-2 genomic sequences were generated from positive samples collected, along with epidemiological metadata, at a walk-up, rapid testing site in the Mission District of San Francisco, California during 22 November to 1 December, 2020, and 10-29 January 2021. Secondary household attack rates and mean sample viral load were estimated and compared across observed variants. RESULTS: A total of 12 124 tests were performed yielding 1099 positives. From these, 928 high-quality genomes were generated. Certain viral lineages bearing spike mutations, defined in part by L452R, S13I, and W152C, comprised 54.4% of the total sequences from January, compared to 15.7% in November. Household contacts exposed to the "California" or "West Coast" variants (B.1.427 and B.1.429) were at higher risk of infection compared to household contacts exposed to lineages lacking these variants (0.36 vs 0.29, risk ratio [RR] = 1.28; 95% confidence interval [CI]: 1.00-1.64). The reproductive number was estimated to be modestly higher than other lineages spreading in California during the second half of 2020. Viral loads were similar among persons infected with West Coast versus non-West Coast strains, as was the proportion of individuals with symptoms (60.9% vs 64.3%). CONCLUSIONS: The increase in prevalence, relative household attack rates, and reproductive number are consistent with a modest transmissibility increase of the West Coast variants. Summary: We observed a growing prevalence and modestly elevated attack rate for "West Coast" severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants in a community testing setting in San Francisco during January 2021, suggesting its modestly higher transmissibility.

Performance Characteristics of a Rapid Severe Acute Respiratory Syndrome Coronavirus 2 Antigen Detection Assay at a Public Plaza Testing Site in San Francisco.

We evaluated the performance of the Abbott BinaxNOW rapid antigen test for coronavirus disease 2019 (Binax-CoV2) to detect virus among persons, regardless of symptoms, at a public plaza site of ongoing community transmission. Titration with cultured severe acute respiratory syndrome coronavirus 2 yielded a human observable threshold between 1.6 × 104-4.3 × 104 viral RNA copies (cycle threshold [Ct], 30.3-28.8). Among 878 subjects tested, 3% (26 of 878) were positive by reverse-transcription polymerase chain reaction, of whom 15 of 26 had a Ct <30, indicating high viral load; of these, 40% (6 of 15) were asymptomatic. Using this Ct threshold (<30) for Binax-CoV2 evaluation, the sensitivity of Binax-CoV2 was 93.3% (95% confidence interval, 68.1%-99.8%) (14 of 15) and the specificity was 99.9% (99.4%-99.9%) (855 of 856).

Field Performance and Public Health Response Using the BinaxNOWTM Rapid Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Antigen Detection Assay During Community-Based Testing.

Among 3302 persons tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by BinaxNOWTM and reverse transcription polymerase chain reaction (RT-PCR) in a community setting, rapid assay sensitivity was 100%/98.5%/89% using RT-PCR cycle thresholds of 30, 35, and no threshold. The specificity was 99.9%. Performance was high across ages and those with and without symptoms. Rapid resulting permitted immediate public health action.

Community Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 Disproportionately Affects the Latinx Population During Shelter-in-Place in San Francisco.

BACKGROUND: There is an urgent need to understand the dynamics and risk factors driving ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission during shelter-in-place mandates. METHODS: We offered SARS-CoV-2 reverse-transcription polymerase chain reaction (PCR) and antibody (Abbott ARCHITECT IgG) testing, regardless of symptoms, to all residents (aged ≥4 years) and workers in a San Francisco census tract (population: 5174) at outdoor, community-mobilized events over 4 days. We estimated SARS-CoV-2 point prevalence (PCR positive) and cumulative incidence (antibody or PCR positive) in the census tract and evaluated risk factors for recent (PCR positive/antibody negative) vs prior infection (antibody positive/PCR negative). SARS-CoV-2 genome recovery and phylogenetics were used to measure viral strain diversity, establish viral lineages present, and estimate number of introductions. RESULTS: We tested 3953 persons (40% Latinx; 41% White; 9% Asian/Pacific Islander; and 2% Black). Overall, 2.1% (83/3871) tested PCR positive: 95% were Latinx and 52% were asymptomatic when tested; 1.7% of census tract residents and 6.0% of workers (non-census tract residents) were PCR positive. Among 2598 tract residents, estimated point prevalence of PCR positives was 2.3% (95% confidence interval [CI], 1.2%-3.8%): 3.9% (95% CI, 2.0%-6.4%) among Latinx persons vs 0.2% (95% CI, .0-.4%) among non-Latinx persons. Estimated cumulative incidence among residents was 6.1% (95% CI, 4.0%-8.6%). Prior infections were 67% Latinx, 16% White, and 17% other ethnicities. Among recent infections, 96% were Latinx. Risk factors for recent infection were Latinx ethnicity, inability to shelter in place and maintain income, frontline service work, unemployment, and household income <$50 000/year. Five SARS-CoV-2 phylogenetic lineages were detected. CONCLUSIONS: SARS-CoV-2 infections from diverse lineages continued circulating among low-income, Latinx persons unable to work from home and maintain income during San Francisco's shelter-in-place ordinance.

The activity of IKCa and BKCa channels contributes to insulin-mediated NO synthesis and vascular tone regulation in human umbilical vein.

Insulin regulates the l-arginine/nitric oxide (NO) pathway in human umbilical vein endothelial cells (HUVECs), increasing the plasma membrane expression of the l-arginine transporter hCAT-1 and inducing vasodilation in umbilical and placental veins. Placental vascular relaxation induced by insulin is dependent of large conductance calcium-activated potassium channels (BKCa), but the role of KCa channels on l-arginine transport and NO synthesis is still unknown. The aim of this study was to determine the contribution of KCa channels in both insulin-induced l-arginine transport and NO synthesis, and its relationship with placental vascular relaxation. HUVECs, human placental vein endothelial cells (HPVECs) and placental veins were freshly isolated from umbilical cords and placenta from normal pregnancies. Cells or tissue were incubated in absence or presence of insulin and/or tetraethylammonium, 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole, iberiotoxin or NG-nitro-l-arginine methyl ester. l-Arginine uptake, plasma membrane polarity, NO levels, hCAT-1 expression and placenta vascular reactivity were analyzed. The inhibition of intermediate-conductance KCa (IKCa) and BKCa increases l-arginine uptake, which was related with protein abundance of hCAT-1 in HUVECs. IKCa and BKCa activities contribute to NO-synthesis induced by insulin but are not directly involved in insulin-stimulated l-arginine uptake. Long term incubation (8 h) with insulin increases the plasma membrane hyperpolarization and hCAT-1 expression in HUVECs and HPVECs. Insulin-induced relaxation in placental vasculature was reversed by KCa inhibition. The results show that the activity of IKCa and BKCa channels are relevant for both physiological regulations of NO synthesis and vascular tone regulation in the human placenta, acting as a part of negative feedback mechanism for autoregulation of l-arginine transport in HUVECs.

Improvement of endothelial function by Gunnera tinctoria extract with antioxidant properties.

BACKGROUND: Gunnera tinctoria has been collected by Mapuche-Pewenche people for food and medicinal purposes. The high polyphenol content of methanolic extract from G. tinctoria leaves with chemical constituents such as ellagic acid and quercetin derivatives suggests its application to prevent endothelial dysfunction and oxidative stress. The aim of this study was to provide evidence of the protective effect of this extract on endothelial function by reducing oxidative stress induced by high D-glucose and H2O2, as well as by stimulating nitric oxide (NO) levels in human umbilical vein endothelial cells (HUVECs). RESULTS: A methanolic extract with a high content of polyphenols (520 ± 30 mg gallic acid equivalents/g dry extract) was obtained from G. tinctoria leaves. Its main constituent was ellagic acid. The results of Ferric reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays of the extract confirmed its antioxidant activity by inhibition pathway of radical species. The incubation of HUVECs with the extract decreased the apoptosis and reactive oxygen species (ROS) synthesis induced by high extracellular concentration of D-glucose or hydrogen peroxide. The extract increased endothelial NO levels and reduced vasoconstriction in human placental vessels. CONCLUSIONS: This study provides evidence about the antioxidant and endothelial protective properties of methanolic G. tinctoria leaf extract. The extract improves the availability of NO in HUVECs, inhibiting the production of ROS and vasoconstriction.

Role of Nb2O5 Crystal Phases on the Photocatalytic Conversion of Lignin Model Molecules and Selectivity for Value-Added Products.

The photocatalytic conversion in aqueous media of phenol and guaiacol as a lignin model compound using Nb2O5 with different crystal phases was studied. Nb2O5 particles were synthesized using hydrothermal methods, where it was observed that changes in the solvent control their morphology and crystal phase. Different photocatalytic behavior of Nb2O5 was observed with the selected model compounds, indicating that its selection directly impacts the resulting conversion and selectivity rates as well as the reaction pathway, highlighting the relevance of model molecule selection. Photocatalytic conversion of phenol showed conversion rate (C%) up to 25 % after 2 h irradiation and high selectivity (S%) to pyrogallol (up to 50 %). Orthorhombic Nb2O5 spheres favored conversion through free hydroxyl radicals while monoclinic rods did not convert phenol. Guaiacol photocatalytic oxidation showed high conversion rate but lower selectivity. Orthorhombic and monoclinic Nb2O5 favored the formation of resorcinol with S % ~0.43 % (C % ~33 %) and ~13 % (C % ~27 %) respectively. The mixture of both phases enhanced the guaiacol conversion rate to ~55 % with ~17 % of selectivity to salicylaldehyde. The use of radical scavengers provided information to elucidate the reaction pathway for these model compounds, showing that different reaction pathways may be obtained for the same photocatalyst if the model compound is changed.

Lessons from Two Latino Communities Working with Academic Partners to Increase Access to COVID-19 Testing.

OBJECTIVE: We sought to examine the experiences of community partners in a community-academic partnership to promote COVID-19 testing in two majority Latino communities. METHODS: We conducted semistructured, in-depth interviews in English and Spanish with community-based organization leaders and community health workers/promotoras (n = 10) from June to July 2021. Interviews focused on identifying partner roles in planning and testing implementation and evaluating communication among partners. Interviews were transcribed and analyzed in ATLAS.ti version 8.4.5. Analyses involved deductive and inductive approaches to identify key themes. RESULTS: Participants described both strengths and challenges to the collaborative approach within each of three core themes: building relationships in the time of COVID-19; uplifting existing community leadership; and commitment of the academic partners and community-based organizations to conduct partnership activities in Spanish. CONCLUSION: Community-academic partnerships that invest in strong relationships, community leadership, and a commitment to the community's preferred language offer a promising approach to addressing COVID-19 testing barriers. Findings provide direction for future research on how community members and academic partners can come together to inform strategies to continue addressing the COVID-19 pandemic.

Degradation of contaminants of emerging concern in a secondary effluent using synthesized MOF-derived photoanodes: A comparative study between photo-, electro- and photoelectrocatalysis.

Three metal-organic framework (MOF)-based photoanodes were prepared by deposition on TiO2 nanotubes using Ti as substrate (Ti/TiO2NT): i) Ti/TiO2NT-Au@ZIF-8, ii) Ti/TiO2NT-Ru3(BTC)2, iii) Ti/TiO2NT-UiO-66(Zr)NH2. These photoanodes were characterized by FEG-SEM, EDX and DRX. The analyses showed a successful modification and a high homogeneity of the different MOFs on the Ti/TiO2NT surface. The photoanodes were studied in the degradation of Contaminants of Emerging Concern (CECs) in a spiked secondary effluent from a Municipal Wastewater Treatment Plant (MWWTP). Sodium diclofenac (DCF), sulfamethazine (SMT) and carbamazepine (CBZ) were used as CECs at low concentration (200 µg/L each CEC). The samples were preconcentrated using Solid Phase Extraction (SPE) and analyzed by a HPLC-DAD system. The MOF-based photoanodes exhibited a high photoelectrochemical (PEC) activity towards the oxidation of CECs, achieving up to 50%, 70% and 80% of removal using Ti/TiO2NT-Au@ZIF-8, Ti/TiO2NT-UiO-66(Zr)NH2, Ti/TiO2NT-Ru3(BTC), respectively. The influence of the generation of hydroxyl radical was then studied. The results indicate that PEC degradation using Ti/TiO2NT-Ru3(BTC)2 and Ti/TiO2NT-UiO-66(Zr)NH2 is more affected by the concentration of the radical.

Intermediate risk of choledocholithiasis: are we on the right path?

The risk of choledocholithiasis should be assessed in every patient undergoing cholecystectomy to define the next step. The American Society for Gastrointestinal Endoscopy proposed a stratified predictor scale of choledocholithiasis. Therefore, we aimed to describe our experience managing patients with an intermediate risk of choledocholithiasis according to the American Society for Gastrointestinal Endoscopy guidelines and the actual presence of bile duct stones in magnetic resonance cholangiopancreatography. Methods: A retrospective observational study with a prospective database was conducted. The analysis included sociodemographic data, laboratory values, and imaging. Bivariate, multivariate, and receiver operating characteristic analysis were performed. Results: Three hundred twenty-seven patients had an intermediate risk for choledocholithiasis. Half the patients were at least 65 years old. 24.77% were diagnosed with choledocholithiasis. Bile duct dilation was documented in only 3.06% of cases. Diagnosis of choledocholithiasis is associated with an age odds ratio (OR): 1.87 (P 0.02), alkaline phosphatase OR: 2.44 (P 0.02), and bile duct dilation greater than 6 mm OR: 14.65 (P 0.00). Conclusions: High variability in the accuracy of imaging techniques results in a large number of patients classified as intermediate risk without choledocholithiasis in cholangioresonance. Therefore, enhancing the criteria to define intermediate risk for patients in order to optimize resources is of paramount importance.

Field assessment of BinaxNOW antigen tests as COVID-19 treatment entry point at a community testing site in San Francisco during evolving omicron surges.

COVID-19 oral treatments require initiation within 5 days of symptom onset. Although antigen tests are less sensitive than RT-PCR, rapid results could facilitate entry to treatment. We collected anterior nasal swabs for BinaxNOW and RT-PCR testing and clinical data at a walk-up, community site in San Francisco, California between January and June 2022. SARS-CoV-2 genomic sequences were generated from positive samples and classified according to subtype and variant. Monte Carlo simulations were conducted to estimate the expected proportion of SARS-CoV-2 infected persons who would have been diagnosed within 5 days of symptom onset using RT-PCR versus BinaxNOW testing. Among 25,309 persons tested with BinaxNOW, 2,799 had concomitant RT-PCR. 1137/2799 (40.6%) were SARS-CoV-2 RT-PCR positive. We identified waves of predominant omicron BA.1, BA.2, BA.2.12, BA.4, and BA.5 among 720 sequenced samples. Among 1,137 RT-PCR positive samples, 788/1137 (69%) were detected by BinaxNOW; 94% (669/711) of those with Ct value <30 were detected by BinaxNOW. BinaxNOW detection was consistent over lineages. In analyses to evaluate entry to treatment, BinaxNOW detected 81.7% (361/442, 95% CI: 77-85%) of persons with COVID-19 within 5 days of symptom onset. In comparison, RT-PCR (24-hour turnaround) detected 84.2% (372/442, 95% CI: 80-87%) and RT-PCR (48-hour turnaround) detected 67.0% (296/442, 95% CI: 62-71%) of persons with COVID-19 within 5 days of symptom onset. BinaxNOW detected high viral load from anterior nasal swabs consistently across omicron sublineages emerging between January and June of 2022. Simulations support BinaxNOW as an entry point for COVID-19 treatment in a community field setting.

Integrating Rapid Diabetes Screening Into a Latinx Focused Community-Based Low-Barrier COVID-19 Testing Program.

Importance: Community-based COVID-19 testing and vaccination programs play a crucial role in mitigating racial and ethnic disparities in COVID-19 service delivery. They also represent a platform that can be leveraged to expand access to testing for chronic diseases, including diabetes, that disproportionately affect the Latinx community and other marginalized communities. Objective: To evaluate outcomes associated with a diabetes testing strategy designed to reach low-income Latinx persons by leveraging COVID-19 testing infrastructure and community trust developed during the COVID-19 pandemic. Design, Setting, and Participants: This health care improvement study was conducted from August 1 to October 5, 2021, at an outdoor, community-based COVID-19 testing site at a transport hub in the Mission Neighborhood in San Francisco, California. Because the program was designed to expand access to diabetes screening to the local community, all individuals presenting for on-site testing were eligible. Data were analyzed in November 2021. Interventions: Integration of rapid, point-of-care hemoglobin A1c screening as a testing option in an existing low-barrier COVID-19 testing program. Main Outcomes and Measures: Evaluation was guided by the Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework and utilized programmatic data and structured surveys among clients and staff. Results: Of 6631 individuals tested (median [IQR] age 39.3 [29.7-51.3] years; 3417 [52.3%] female, 4348 [65.6%] Latinx), 923 (13.9%) underwent hemoglobin A1c testing with or without COVID-19 testing and 5708 (86.1%) underwent COVID-19 testing only. Individuals tested for diabetes were more likely to be Latinx (763 of 923 individuals [82.7%] who underwent testing were Latinx vs 3585 of 5708 [62.8%] not undergoing testing), have an annual household income of less than $50 000 (450 individuals [81.2%] vs 2409 individuals [66.0%]), and not have health insurance (381 individuals [47.2%] vs 1858 individuals [39.9%]), and 206 (48.0%) had never tested for diabetes before. Overall, 313 (33.9%) and 113 (12.2%) individuals had prediabetes and diabetes, respectively; only 141 of 354 of these individuals (39.8%) had a primary care clinician whom they had seen in the prior 12 months, which was lower among Latinx individuals (113 of 307 individuals [36.8%] vs 28 of 47 [59.6%]). Acceptability of the rapid testing program was high-98% were satisfied with their visit and 96% said they would return for future services; key factors underpinning acceptability included friendly staff, efficiency, and a convenient location. Conclusions and Relevance: In this health care improvement study conducted within an existing community-based COVID-19 testing program, integrating rapid testing for diabetes was feasible, reached low-income Latinx individuals, and identified many persons with prediabetes and diabetes, most of whom lacked access to services in formal health care settings. Leveraging pandemic-related public health responses represents an important opportunity for engaging socioeconomically disadvantaged populations into care for diabetes.

Viral Load Among Vaccinated and Unvaccinated, Asymptomatic and Symptomatic Persons Infected With the SARS-CoV-2 Delta Variant.

We found no significant difference in cycle threshold values between vaccinated and unvaccinated persons infected with severe acute respiratory syndrome coronavirus 2 Delta, overall or stratified by symptoms. Given the substantial proportion of asymptomatic vaccine breakthrough cases with high viral levels, interventions, including masking and testing, should be considered in settings with elevated coronavirus disease 2019 transmission.

New STAG3 gene variant as a cause of premature ovarian insufficiency / Nueva variante del gen STAG3 causante de insuficiencia ovárica prematura

Objectives: To describe a case of ovarian failure secondary to a homozygous pathogenic variant in the STAG3 gene not previously reported. Materials and Methods: A 16-year-old patient with primary amenorrhea and absence of secondary sexual characteristics, with documented autoimmune hypothyroidism, poor genital and gonadal streak development which prompted the performance of clinical exome sequencing. A homozygous pathogenic variant not previously reported in the STAG3 gene, which has been associated with premature ovarian insufficiency (POI), was identified. Conclusions: In this case, clinical exome sequencing was key for identifying a STAG gene abnormality, probably associated with POI and long term prognosis for the patient. A new pathogenic variant c.2773delT; p.Ser925Profs*6 of the STAG3 gene associated with POI was established.

Objetivos: describir un caso de falla ovárica secundaria a una variante patogénica homocigota en el gen STAG3 no reportada previamente. Materiales y métodos: paciente de 16 años con amenorrea primaria y ausencia de características sexuales secundarias, en quien se documentó hipotiroidismo autoinmune, pobre desarrollo genital y cintilla gonadal, por lo cual se realizó secuenciación de exoma clínico. Se identificó una variante homocigota patogénica previamente no reportada en el gen STAG3, el cual ha sido relacionado con insuficiencia ovárica prematura (IOP). Conclusiones: en este caso, la realización de exoma clínico fue determinante para identificar una alteración del gen STAG, probablemente asociada a la IOP y el pronóstico a largo plazo de la paciente. Se establece una nueva variante patogénica c.2773delT; p.Ser925Profs*6 del gen STAG3 asociada a la IOP.

COVID-19 Symptoms and Duration of Rapid Antigen Test Positivity at a Community Testing and Surveillance Site During Pre-Delta, Delta, and Omicron BA.1 Periods.

Importance: Characterizing the clinical symptoms and evolution of community-based SARS-CoV-2 infections may inform health practitioners and public health officials in a rapidly changing landscape of population immunity and viral variants. Objectives: To compare COVID-19 symptoms among people testing positive with a rapid antigen test (RAT) during the Omicron BA.1 variant period (December 1, 2021, to January 30, 2022) with the pre-Delta (January 10 to May 31, 2021) and Delta (June 1 to November 30, 2021) variant periods and to assess the duration of RAT positivity during the Omicron BA.1 surge. Design, Setting, and Participants: This cross-sectional study was conducted from January 10, 2021, to January 31, 2022, at a walk-up community COVID-19 testing site in San Francisco, California. Participants included children and adults seeking COVID-19 testing with an RAT, regardless of age, vaccine status, or symptoms. Main Outcomes and Measures: Fisher exact tests or χ2 tests were used to compare COVID-19 symptoms during the Omicron BA.1 period with the pre-Delta and Delta periods for vaccination status and age group. Among people returning for repeated testing during the Omicron period, the proportion with a positive RAT between 4 and 14 days from symptom onset or since first positive test if asymptomatic was estimated. Results: Among 63 277 persons tested (median [IQR] age, 32 [21-44] years, with 12.0% younger than 12 years; 52.0% women; and 68.5% Latinx), a total of 18 301 people (28.9%) reported symptoms, of whom 4565 (24.9%) tested positive for COVID-19. During the Omicron BA.1 period, 3032 of 7283 symptomatic participants (41.6%) tested positive, and the numbers of these reporting cough and sore throat were higher than during pre-Delta and Delta periods (cough: 2044 [67.4%] vs 546 [51.3%] of 1065 participants, P < .001 for pre-Delta, and 281 [60.0%] of 468 participants, P = .002, for Delta; sore throat: 1316 [43.4%] vs 315 [29.6%] of 1065 participants, P < .001 for pre-Delta, and 136 [29.1%] of 468 participants, P < .001, for Delta). Compared with the 1065 patients with positive test results in the pre-Delta period, congestion among the 3032 with positive results during the Omicron BA.1 period was more common (1177 [38.8%] vs 294 [27.6%] participants, P < .001), and loss of taste or smell (160 [5.3%] vs 183 [17.2%] participants, P < .001) and fever (921 [30.4%] vs 369 [34.7%] participants, P = .01) were less common. In addition, during the Omicron BA.1 period, fever was less common among the people with positive test results who had received a vaccine booster compared with those with positive test results who were unvaccinated (97 [22.5%] of 432 vs 42 [36.2%] of 116 participants, P = .003), and fever and myalgia were less common among participants who had received a booster compared with those with positive results who had received only a primary series (fever: 97 [22.5%] of 432 vs 559 [32.8%] of 1705 participants, P < .001; myalgia: 115 [26.6%] of 432 vs 580 [34.0%] of 1705 participants, P = .003). During the Omicron BA.1 period, 5 days after symptom onset, 507 of 1613 people (31.1%) with COVID-19 stated that their symptoms were similar, and 95 people (5.9%) reported worsening symptoms. Among people testing positive, 80.2% of participants who were symptomatic and retested remained positive 5 days after symptom onset. Conclusions and Relevance: In this cross-sectional study, COVID-19 upper respiratory tract symptoms were more commonly reported during the Omicron BA.1 period than during the pre-Delta and Delta periods, with differences by vaccination status. Rapid antigen test positivity remained high 5 days after symptom onset, supporting guidelines requiring a negative test to inform the length of the isolation period.

Reproducibility and implementation of a rapid, community-based COVID-19 "test and respond" model in low-income, majority-Latino communities in Northern California.

OBJECTIVE: To evaluate implementation of a community-engaged approach to scale up COVID-19 mass testing in low-income, majority-Latino communities. METHODS: In January 2021, we formed a community-academic "Latino COVID-19 Collaborative" with residents, leaders, and community-based organizations (CBOs) from majority-Latinx, low-income communities in three California counties (Marin/Merced/San Francisco). The collaborative met monthly to discuss barriers/facilitators for COVID-19 testing, and plan mass testing events informed by San Francisco's Unidos en Salud "test and respond" model, offering community-based COVID-19 testing and post-test support in two US-census tracts: Canal (Marin) and Planada (Merced). We evaluated implementation using the RE-AIM framework. To further assess testing barriers, we surveyed a random sample of residents who did not attend the events. RESULTS: Fifty-five residents and CBO staff participated in the Latino collaborative. Leading facilitators identified to increase testing were extended hours of community-based testing and financial support during isolation. In March-April 2021, 1,217 people attended mass-testing events over 13 days: COVID-19 positivity was 3% and 1% in Canal and Planada, respectively. The RE-AIM evaluation found: census tract testing coverage of 4.2% and 6.3%, respectively; 90% of event attendees were Latino, 89% had household income <$50,000/year, and 44% first-time testers (reach), effectiveness in diagnosing symptomatic cases early (median isolation time: 7 days) and asymptomatic COVID-19 (41% at diagnosis), high adoption by CBOs in both counties, implementation of rapid testing (median: 17.5 minutes) and disclosure, and post-event maintenance of community-based testing. Among 265 non-attendees surveyed, 114 (43%) reported they were aware of the event: reasons for non-attendance among the 114 were insufficient time (32%), inability to leave work (24%), and perceptions that testing was unnecessary post-vaccination (24%) or when asymptomatic (25%). CONCLUSION: Community-engaged mass "test and respond" events offer a reproducible approach to rapidly increase COVID-19 testing access in low-income, Latinx communities.

High Likelihood of Accepting COVID-19 Vaccine in a Latinx Community at High SARS-CoV-2 Risk in San Francisco.

Of 4133 persons surveyed at a low-barrier coronavirus disease 2019 (COVID-19) test site with high positivity in an urban Latinx community in January 2021, 86% indicated that they would accept a COVID-19 vaccination. The top reasons for vaccine hesitancy included concerns around side effects and safety and distrust of health care systems.

High Parental Vaccine Motivation at a Neighborhood-Based Vaccine and Testing Site Serving a Predominantly Latinx Community.

Purpose: To understand vaccine attitudes of Latinx parents highly impacted by COVID-19. Methods: In April 2021, we surveyed parents about their attitudes for COVID-19 vaccination of their children at a community-based outdoor testing/vaccination site serving predominantly low-income Latinx persons in San Francisco. Results: Among 1033 parents (75% Latinx), 92% would "definitely" or "probably" vaccinate their children. Vaccine concerns were higher for younger children and included side effects and impacts on fertility. Doctors and community organizations were noted as trusted sources of information, including among vaccine-concerned parents. Conclusion: Latinx parents accessing neighborhood-based COVID-19 testing/vaccination services are highly motivated to vaccinate their children for COVID-19.