Search

Objectives: This study aims to quantify the degree to which an underserved, Hispanic population in Los Angeles is impacted by SARS-CoV-2, and determine factors associated with paediatric seropositivity., Design: Cross-sectional., Setting: AltaMed, a Federally Qualified Health Center in Los Angeles., Participants: A random sample of households who had received healthcare at AltaMed Medical Group was invited to participate. Households with at least one adult and one paediatric participant between 5 and 17 years of age were eligible to participate. Consented participants completed a survey on social determinants of health and were tested for antibodies using Abbott Architect SARS-CoV-2-IgG and SARS-CoV-2-IgM tests., Primary Outcome Measure: Seropositive status., Results: We analysed 390 adults (mean age in years, 38.98 (SD 12.11)) and 332 paediatric participants (11.26 (SD 3.51)) from 196 households. Estimated seropositivity was 52.11% (95% CI 49.61% to 55.19%) in paediatric participants and 63.58% (95% CI 60.39% to 65.24%) in adults. Seropositivity was 11.47% (95% CI 6.82% to 14.09%) lower in paediatric participants, but high relative to other populations. A household member with type 2 diabetes (OR 2.94 (95% CI 1.68 to 5.14)), receipt of food stamps (OR 1.66 (95% CI 1.08 to 2.56)) and lower head-of-household education (OR 1.73 (95% CI 1.06 to 2.84)) were associated with paediatric seropositivity., Conclusions: SARS-CoV-2 seropositivity is high in Hispanic children and adolescents in Los Angeles. Food insecure households with low head-of-household education, and at least one household member with type 2 diabetes, had the highest risk. These factors may inform paediatrician COVID-19 mitigation recommendations., Trial Registration Number: NCT04901624., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The objective of this analysis was to compare the performance sensitivity and specificity of manufacturer-recommended signal-to-cutoff (S/Co) thresholds with modified S/Co values to estimate the prevalence of SARS-CoV-2-specific antibodies in a cohort of firefighters with a known infection history., Methods: Plasma venipuncture samples were used for serologic analysis of firefighters in Los Angeles, CA, USA, in October 2020. Seropositivity was assessed using the manufacturer's recommended S/Co (≥1.4 IgG) and modified S/Co thresholds based on measured antibody levels in 178 negative control patients who had blood drawn prior to the emergence of COVID-19. Optimal S/Co threshold was determined by receiver operating characteristic (ROC) curve analysis., Results: Of 585 firefighters included in the study, 52 (8.9%) reported having a PCR-positive test history prior to antibody testing. Thirty-five (67.3%) firefighters with a previous PCR-positive test were seropositive based on the manufacturer S/Co thresholds, consistent with an estimated 67.3% sensitivity and 100% specificity. After evaluating multiple modified S/Co thresholds based on pre-pandemic negative samples, a modified S/Co of 0.36 was found to yield optimal sensitivity (88.5%) and specificity (99.4%) by ROC curve analysis. This modified threshold improved serostatus classification accuracy by 21.2%., Conclusions: S/Co thresholds based on known negative samples significantly increase seropositivity and more accurately estimate cumulative incidence of disease compared to manufacturer-based thresholds., Competing Interests: Authors’ Disclosures or Potential Conflicts of Interest: Upon manuscript submission, all authors completed the author disclosure form. Disclosures and/or potential conflicts of interest: Employment or Leadership: None declared. Consultant or Advisory Role: N. Sood, Payssurance and American Medical Association. Stock Ownership: None declared. Honoraria: None declared. Research Funding: O. Toubat is supported in part by the National Heart, Lung, and Blood Institute of the National Institutes of Health under award number F30HL154324 outside of the submitted work. A.H. Berg is supported in part by grants from the National Institutes of Health outside of the submitted work. J. Bhattacharya is supported in part by grants from the National Institutes of Health outside of the submitted work. N. Sood received funding and in-kind support from the Burns and Allen Research Institute at Cedars-Sinai Medical Center, Mayor’s Office City of Los Angeles, Rockefeller Foundation, Abbott Diagnostics, and the Conrad R. Hilton Foundation for the study, and grants from the Agency for Healthcare Research and Quality, the National Institutes of Health, Health Care Services Corporation, and the Patient-Centered Outcomes Research Institute outside the submitted work. Expert Testimony: None declared. Patents: None declared. Other Remuneration: K. Mulligan, personal fees from Precision Health Economics; N. Sood, personal fees from the China Development Research Foundation, PhRMA, MDL law firms, Precision Health Economics, and H&H Wholesale; J. Bhattacharya, personal fees from Acumen LLC., (© American Association for Clinical Chemistry 2022. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: We estimate the seroprevalence of SARS-CoV-2 antibodies among a sample of firefighters in the Los Angeles (LA), California fire department in October 2020 and compare demographic and contextual factors for seropositivity., Methods: We conducted a serological survey of firefighters in LA, California, USA, in October 2020. Individuals were classified as seropositive for SARS-CoV-2 if they tested positive for IgG, IgM or both. We compared demographic and contextual factors for seropositivity., Results: All firefighters in LA, California, USA were invited to participate in our study, but only roughly 21% participated. Of 713 participants with valid serological data, 8.8% tested positive for SARS-CoV-2 antibodies, and among the 686 with complete survey data 8.9% tested positive for antibodies. Seropositivity was not associated with gender, age or race/ethnicity. Seropositivity was highest among firefighters who reported working in the vicinity of LA International Airport, which had a known outbreak in July 2020., Conclusions: Seroprevalence among firefighters in our sample was 8.8%, however, we lack a full workplace seroprevalence estimate to compare the relative magnitude against general population seroprevalence (15%). Workplace safety protocols, such as access to personal protective equipment and testing, can mitigate increased risk of infection at work, and may have eliminated differences in disease burden by geography and race/ethnicity in our sample., Competing Interests: Competing interests: NS reported receiving funding and in-kind support from Burns and Allen Research Institute at Cedars-Sinai Medical Center, Mayor’s Office City of Los Angeles, Rockefeller Foundation, Abbott Diagnostics and Conrad R. Hilton Foundation for the study., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: We sought to determine the extent of SARS-CoV-2 seroprevalence and the factors associated with seroprevalence across a diverse cohort of healthcare workers., Design: Observational cohort study of healthcare workers, including SARS-CoV-2 serology testing and participant questionnaires., Settings: A multisite healthcare delivery system located in Los Angeles County., Participants: A diverse and unselected population of adults (n=6062) employed in a multisite healthcare delivery system located in Los Angeles County, including individuals with direct patient contact and others with non-patient-oriented work functions., Main Outcomes: Using Bayesian and multivariate analyses, we estimated seroprevalence and factors associated with seropositivity and antibody levels, including pre-existing demographic and clinical characteristics; potential COVID-19 illness-related exposures; and symptoms consistent with COVID-19 infection., Results: We observed a seroprevalence rate of 4.1%, with anosmia as the most prominently associated self-reported symptom (OR 11.04, p<0.001) in addition to fever (OR 2.02, p=0.002) and myalgias (OR 1.65, p=0.035). After adjusting for potential confounders, seroprevalence was also associated with Hispanic ethnicity (OR 1.98, p=0.001) and African-American race (OR 2.02, p=0.027) as well as contact with a COVID-19-diagnosed individual in the household (OR 5.73, p<0.001) or clinical work setting (OR 1.76, p=0.002). Importantly, African-American race and Hispanic ethnicity were associated with antibody positivity even after adjusting for personal COVID-19 diagnosis status, suggesting the contribution of unmeasured structural or societal factors., Conclusion and Relevance: The demographic factors associated with SARS-CoV-2 seroprevalence among our healthcare workers underscore the importance of exposure sources beyond the workplace. The size and diversity of our study population, combined with robust survey and modelling techniques, provide a vibrant picture of the demographic factors, exposures and symptoms that can identify individuals with susceptibility as well as potential to mount an immune response to COVID-19., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)

Importance: Certain individuals, when infected by SARS-CoV-2, tend to develop the more severe forms of Covid-19 illness for reasons that remain unclear., Objective: To determine the demographic and clinical characteristics associated with increased severity of Covid-19 infection., Design: Retrospective observational study. We curated data from the electronic health record, and used multivariable logistic regression to examine the association of pre-existing traits with a Covid-19 illness severity defined by level of required care: need for hospital admission, need for intensive care, and need for intubation., Setting: A large, multihospital healthcare system in Southern California., Participants: All patients with confirmed Covid-19 infection (N = 442)., Results: Of all patients studied, 48% required hospitalization, 17% required intensive care, and 12% required intubation. In multivariable-adjusted analyses, patients requiring a higher levels of care were more likely to be older (OR 1.5 per 10 years, P<0.001), male (OR 2.0, P = 0.001), African American (OR 2.1, P = 0.011), obese (OR 2.0, P = 0.021), with diabetes mellitus (OR 1.8, P = 0.037), and with a higher comorbidity index (OR 1.8 per SD, P<0.001). Several clinical associations were more pronounced in younger compared to older patients (Pinteraction<0.05). Of all hospitalized patients, males required higher levels of care (OR 2.5, P = 0.003) irrespective of age, race, or morbidity profile., Conclusions and Relevance: In our healthcare system, greater Covid-19 illness severity is seen in patients who are older, male, African American, obese, with diabetes, and with greater overall comorbidity burden. Certain comorbidities paradoxically augment risk to a greater extent in younger patients. In hospitalized patients, male sex is the main determinant of needing more intensive care. Further investigation is needed to understand the mechanisms underlying these findings., Competing Interests: The authors have declared that no competing interests exist.