Did Risk-based or Age-based Vaccine Prioritization for Covid-19 Save More Lives? (preprint)

Importance: All U.S. states provided Covid-19 vaccine access to frontline healthcare workers first, but after that, states varied in whether they gave earlier access to the elderly, versus the vulnerable with co-morbidities, or school employees or essential workers, reflecting the underlying scientific and policy uncertainty. Objective: To evaluate if risk-based or age-based prioritization is more effective at reducing reported Covid-19 cases and deaths. Design: A serial cross-sectional study Setting: 50 U.S. states and Washington D.C. Participants: 60+ years of age, high-risk individuals, K-12 school employees, and essential workers Main Outcomes and Measures: Hospitalizations and deaths Results: Seven to nine weeks after 60-year-olds became eligible for a vaccine, there was a statistically significant 40-50% decline in Covid-19 hospitalizations in that state. In contrast, there was no statistically detectable change in hospitalizations in the 7-9 weeks after K-12 employees become eligible for vaccines. Vaccine eligibility of high-risk adults and essential workers produces effects somewhere in the middle, with reductions in hospitalization of about 25%. There was a large statistically significant decline in death rates (25-38%) 10 to 11 weeks after people aged over 60 became vaccine-eligible. These effects were generally statistically larger than high risk individuals, K-12 school employees, and essential workers. Conclusions and Relevance: Panel data analysis of weekly variation in Covid-19 health outcomes reveals that prioritizing adults 60+ years of age is associated with the largest reduction in hospitalizations and Covid-19 cases, followed by vaccines for adults with high-risk comorbidities. Vaccinations extended to K-12 school employees and essential workers is associated with the smallest reductions in hospitalizations and deaths.

Presence of Mediastinal Lymphadenopathy in Hospitalized Covid-19 Patients in a Tertiary Care Hospital in Pakistan - A cross-sectional study (preprint)

BackgroundThe aim of this study was to investigate the presence of mediastinal lymphadenopathy in hospitalized Covid-19 patients in a tertiary care hospital in the metropolitan city of Lahore, Pakistan from September 2020 till July 2021. MethodsWe retrospectively collected data of Covid-19 patients hospitalized from September 2020 till July 2021. Only those patients who tested PCR positive through a nasopharyngeal swab, were enrolled in the study. Patients whose data were missing were excluded from this study. Our exclusion criteria included patients who tested negative on Covid-19 PCR, patients with comorbidities that may cause enlarged mediastinal lymphadenopathies such as haemophagocytic lymphohistiocytosis, neoplasia, tuberculosis, sarcoidosis or a systemic disease. The extent of lung involvement in Covid-19 patients was quantified by using a 25-point visual quantitative assessment called the Chest Computed Tomography Score. This score was then correlated with the presence of mediastinal lymphadenopathy. FindingsOf the 210 hospitalized patients included in the study, 131 (62.4%) had mediastinal lymphadenopathy. The mean and median Severity Score of Covid-19 patients with mediastinal lymphadenopathy (mean: 17.1, SD:5.7; median: 17, IQR: 13-23) were higher as compared to those without mediastinal lymphadenopathy (mean: 12.3, SD:5.4; median: 12, IQR:9-16) InterpretationOur study documents a high prevalence of mediastinal lymphadenopathy in hospitalized patients with Covid-19 with the severity score being higher in its presence representing a more severe course of disease.

COVID-19 related social distancing measures and reduction in city mobility (preprint)

In the absence of any pharmacological intervention, one approach to slowing the COVID-19 pandemic is reducing the contact rate in the population through social distancing. Governments the world over have instituted different measures to increase social distancing but information on their effectiveness in reducing mobility is lacking. We analyzed the mobility data from 41 cities to look at the effect of these interventions. The median mobility across cities on March 2, 2020 was 100% (IQR: 94%, 107%), which decreased to a median of 10% (IQR: 7%, 17%) on March 26, 2020. We found that the mobility decreased on average by 3.4% (95%CI: 3.3%, 3.6%) per day from March 2 through March 26. Social distancing measures decreased the mobility by an additional 23% (95%CI: 20%, 27%). Our study provides initial evidence for the reduction in mobility in cities instituting social distancing measures.