Result for
Tag: transmission
December 14, 2020
Household Transmission of SARS-CoV-2: A Systematic Review and Meta-Analysis
A meta-analysis of 54 studies including 77,758 participants estimated an overall household secondary transmission rate of SARS-CoV-2 of 17% (95% CI 14%-19%). The rate was higher from symptomatic index cases than from asymptomatic index cases (18% vs. 1%), to adult contacts than to child contacts (28% vs. 17%), to spouses than to other family contacts…
On the Concentration of SARS-CoV-2 in Outdoor Air and the Interaction with Pre-Existing Atmospheric Particles
An environmental modeling study of respiratory emissions reported a very low probability of airborne transmission of SARS-CoV-2 (< 1 RNA copy/m3) through respiratory aerosol in outdoor public areas using the environmental characteristics of the cities Milan and Bergamo in northern Italy. Belosi et al. (Dec 8, 2020). On the Concentration of SARS-CoV-2 in Outdoor Air…
December 11, 2020
SARS-CoV-2, SARS-CoV, and MERS-CoV viral load dynamics, duration of viral shedding, and infectiousness: a systematic review and meta-analysis
A meta-analysis of viral RNA shedding of SARS-CoV-2 (79 studies, 5,340 individuals), SARS-CoV (8 studies, 1,858 individuals), and MERS-CoV (11 studies, 799 individuals) found the mean duration of SARS-CoV-2 RNA shedding was 17 days in upper respiratory tract, 14.6 days in lower respiratory tract, 17.2 days in stool, and 16.6 days in serum samples. No…
High Frequency and Prevalence of Community-Based Asymptomatic SARS-CoV-2 Infection
[Pre-print, not peer reviewed] Among 730,000 SARS-CoV-2 test results from Los Angeles from August to October 2020, a higher prevalence of SARS-CoV-2 asymptomatic infection was identified among individuals who reported work in construction compared to other occupations and who identified as members of racial and ethnic minority groups. The prevalence of asymptomatic infection among Hispanic…
Phylogenetic analysis of SARS-CoV-2 in Boston highlights the impact of superspreading events
An analysis using 772 complete SARS-CoV-2 genomes collected in Boston in February and March 2020 and genomes published by the Global Initiative on Sharing All Influenza Data found numerous introductions of the virus in the Boston area, including two superspreading events. One event was an international business conference in Boston held in February, from which…
December 10, 2020
Transmissibility of COVID-19 Depends on the Viral Load around Onset in Adult and Symptomatic Patients
In a retrospective study of 28 COVID-19 patients in Japan, median viral load at initial sample collection was significantly higher in symptomatic than asymptomatic patients, and also higher among adults than children. Among symptomatic patients (n=18), median viral load was consistently higher in patients identified as household cluster index cases than in non-index cases up…
Outbreak of SARS-CoV-2 Infection at a Large Refugee Shelter in Toronto, April 2020: A Clinical and Epidemiologic Descriptive Analysis
A high rate of SARS-CoV-2 infection was identified among residents in a large refugee shelter in Toronto in April 2020, with 25 (41.7%) of 60 adults testing positive. Only 5 (20%) residents were symptomatic at the time of testing, while 21 (87.5%) were symptomatic 14 days after testing. The authors state these results highlight the…
December 9, 2020
SARS-CoV-2 Infection and Transmission in Educational Settings: A Prospective, Cross-Sectional Analysis of Infection Clusters and Outbreaks in England
The risk of SARS-CoV-2 infections and outbreaks were low in educational settings since reopening in the summer half-term in England, with the likelihood of a school outbreak strongly associated with the regional level of COVID-19 incidence. A prospective cohort study among 57,600 educational settings in England reported that there were 113 educational settings in which…
December 8, 2020
SARS-Coronavirus-2 Cases in Healthcare Workers May Not Regularly Originate from Patient Care: Lessons from a University Hospital on the Underestimated Risk of Healthcare Worker to Healthcare Worker Transmission
Investigation of 4 healthcare-associated SARS-CoV-2 outbreaks at a hospital in Germany resulting in 24 infected people suggests healthcare worker (HCW)-to-HCW transmission as the primary mechanism of spread rather than patient-to-HCW transmission. Further investigation showed multiple unprotected contacts between infected HCWs, and no further outbreaks were reported after implementation of contact tracing, testing, physical distancing and…
Evaluation of Rooming-in Practice for Neonates Born to Mothers With Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Italy
It may be possible to effectively mitigate the risk of mother-to-infant transmission of SARS-CoV-2 infection, based on findings from a multi-cohort study of mother-infant dyads (n=62 neonates, 61 mothers) in Italy that found no positive results among neonates 24 hours after birth despite a 95% breastfeeding rate. Infected mothers observed contact precautions such as handwashing…
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