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Tag: transmission
March 2, 2021
Reducing COVID-19 Airborne Transmission Risks on Public Transportation Buses An Empirical Study on Aerosol Dispersion and Control
[Pre-print, not peer-reviewed] Mask wearing in a transit or school bus setting could reduce the overall particle count released into the bus by an average of 50% or more (depending on mask quality), and could reduce the dispersion distance by several feet, according to an experimental study. The study conducted 84 test runs totaling 124…
March 1, 2021
Household Transmission of SARS-CoV-2
A retrospective cohort study of COVID-19 risk among exposed children and adults in households where an index case was diagnosed found an overall infection risk of 10.1%, with median time to diagnosis of 3 days after positive diagnosis of the index case. The study used home addresses recorded in electronic health records to identify the…
Incubation Period for COVID-19: A Systematic Review and Meta-Analysis
A systematic review and meta-analysis (n = 15 studies, 6,300 patients) estimated that the incubation period for SARS-CoV-2 is 5.7 days (range: 5.2-6.3 days). Data were included through March 31, 2020, and most of the studies included in the meta-analysis used different parametric distributions for calculating the pooled incubation period. Rai et al. (Feb 23,…
Retail Store Customer Flow and COVID-19 Transmission
A mathematical model analyzing retail customer flow and SARS-CoV-2 transmission found that then restricting customers to one-way movement could reduce transmission rates to less than one-third of the rate with two-way movement, if all customers comply and transmission occurs primarily through close contact. The model was calibrated using published epidemiologic data and predicted that for…
February 26, 2021
Risk Factors Associated With COVID-19 Transmission Among US Air Force Trainees in a Congregant Setting
A higher number of symptoms and higher viral loads were associated with subsequent clusters of SARS-CoV-2 cases among cohorts of US Air Force basic trainees. Among 10,613 US Air Force basic trainees, of whom 3% (403) received a diagnosis of COVID-19 during the study period, higher numbers of symptoms and higher viral loads (lower cycle…
February 25, 2021
Household Secondary Attack Rate of COVID-19 by Household Size and Index Case Characteristics
[Pre-print, not peer-reviewed] A population-wide study in Ontario, Canada including nearly 85,000 household contacts from nearly 30,000 households between July to November 2020 found that, while the overall household secondary attack rate (SAR) for SARS-CoV-2 transmission was 20%, 12% of households had a SAR ≥75%. Households in which the index case was symptomatic and had…
SARS-CoV-2 Detection and Genomic Sequencing from Hospital Surface Samples Collected at UC Davis
[Pre-print, not peer-reviewed] Environmental samples (n=224) collected from COVID-19 patient serving and staff congregation areas in a university hospital in California between April and August 2020 identified 11 samples positive for SARS-CoV-2 RNA, with a smaller proportion of positive samples (2% vs 11%) detected over time as improved cleaning and patient management practices were implemented. …
A Novel SARS-CoV-2 Variant of Concern B.1.526 Identified in New York
[Pre-print, not peer-reviewed] The prevalence of SARS-CoV-2 isolates with the E484K mutation, a key mutation of the B.1.351 variant, rose from 1.3% to 12.3% between November 2020 to mid-February 2021 in New York City. In a subset of 65 samples suspected to contain key mutations, 49 fell within a single novel lineage (B.1.526) characterized by…
February 24, 2021
Community Transmission of SARS-CoV-2 at Three Fitness Facilities — Hawaii, June–July 2020
An outbreak of COVID-19 cases occurred that was linked to a fitness instructor resulting in cases at 3 fitness facilities, with the highest attack rate (95%) occurring in classes that were taught <1 day before the onset of symptoms in the instructor. Twenty-one cases of COVID-19 were linked to an index case fitness instructor in…
COVID-19 Outbreak Among Attendees of an Exercise Facility — Chicago, Illinois, August–September 2020
A large outbreak of COVID-19 occurred among attendees of indoor high-intensity classes at a Chicago exercise facility in August, 2020, with 55 cases identified among 81 attendees (68% attack rate). All classes were held at reduced capacity (<25%), temperature checks were required upon entry, and participants were required to space mats at least 6 feet…
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