Result for
Topic: Transmission
September 3, 2020
Towards Improved Social Distancing Guidelines Space and Time Dependence of Virus Transmission from Speech-Driven Aerosol Transport Between Two Individuals
[Pre-print, not peer reviewed] A modeling analysis considering air flow and aerosol transport parameters suggests that physical distancing guidelines should also include a contact time recommendation. The authors recommend less than 5 minutes of contact at a distance of one meter apart and less than 15 minutes for two meters apart in scenarios where an…
Temporal Profile and Determinants of Viral Shedding and of Viral Clearance Confirmation on Nasopharyngeal Swabs from SARS-CoV-2-Positive Subjects: A Population-Based Prospective Cohort Study in Reggio Emilia, Italy
Sixty percent (704/1162) of patients with confirmed COVID-19 did not have detectable SARS-CoV-2 RNA on a subsequent nasopharyngeal sample at a median time of 30 days (IQR 23-40) from diagnosis and 36 days (IQR (28-45) from symptom onset. However, 21% of participants with a negative sample had a subsequent positive sample, suggesting a high false…
September 1, 2020
Community Outbreak Investigation of SARS-CoV-2 Transmission Among Bus Riders in Eastern China
In a community outbreak involving two buses with indoor air recirculation on a 100-minute roundtrip to attend a worship event in Zhejiang province, passengers in the bus that had the index case had a 34% higher risk of getting COVID-19 compared to the other bus. Dividing seats on the exposed bus into high- and low-risk…
Outbreak of COVID-19 in a Nursing Home Associated with Aerosol Transmission as a Result of Inadequate Ventilation. Clinical Infectious Diseases
Inadequate ventilation may promote aerosol transmission, as suggested by an outbreak in one of the wards of a Dutch nursing home that was recently renovated with a ventilation system that only circulates outside air when the indoor CO2 concentration is below a certain concentration. Over 6 days, this ward reported 17 (81%) residents and 17…
August 28, 2020
Systematic Review with Meta-Analysis: SARS-CoV-2 Stool Testing and the Potential for Faecal-Oral Transmission
A systematic review of stool testing for SARS-CoV-2 (95 studies) showed that 934/2149 (43%) patients tested positive by stool sample or by anal swab, with positive results up to 70 days after symptom onset. Fecal samples of 282/443 (64%) remained positive even after respiratory samples became negative, for a mean of 12.5 days, and viable…
August 27, 2020
Effectiveness of Surgical, KF94, and N95 Respirator Masks in Blocking SARS-CoV-2: A Controlled Comparison in 7 Patients
Kim et al. detected SARS-CoV-2 RNA by PCR on petri dishes placed in front of patients with SARS-CoV-2 infection in 3/7 patients who coughed while wearing a surgical mask, but in 0/7 petri dishes from similar experiments with the same patients wearing N95 masks and similar KF94 masks. Additionally, researchers detected viral RNA in swabs…
August 25, 2020
Prevalence of SARS-CoV-2 Infection in Children Without Symptoms of Coronavirus Disease 2019
• The prevalence of SARS-CoV-2 infection in asymptomatic children (n=33,041) from across the US who were tested for SAR-CoV-2 when presenting for surgical or medical care was strongly correlated with the prevalence of SARS-CoV-2 in the general population in the communities in which the children lived. The authors present a method to estimate the prevalence…
Phylogenetic Analysis of SARS-CoV-2 in the Boston Area Highlights the Role of Recurrent Importation and Superspreading Events
[pre-print, not peer-reviewed] Lemieux et al. conducted phylogenetic analyses on 772 complete SARS-CoV-2 genomes from the Boston area and found that, since the beginning of the epidemic, there were over 80 introductions into the Boston area, primarily from other parts of the United States and Europe. Investigators studied two distinct superspreading events captured in the…
August 24, 2020
SARS-CoV-2 Community Transmission Disproportionately Affects Latinx Population during Shelter-in-Place in San Francisco
Chamie et al. tested 3,953 people who live or work within a census block in San Francisco and found a point prevalence of SARS-CoV-2 infection (by PCR) of 2% and an estimated cumulative incidence (by antibody testing) of 6%. Among those with positive PCR tests, 95% were Latinx and 53% were asymptomatic when tested. Among…
Asymptomatic Transmission of SARS-CoV-2 on Evacuation Flight. Emerging Infectious Diseases
Bae et al. report a single incidence of possible transmission of COVID-19 during an evacuation flight from Italy to South Korea. After airport screening, 299 asymptomatic passengers took an 11-hour flight to South Korea, during which most of them wore N95 respirators at all times. They were tested for SARS-CoV-2 by RT-PCR on days 1…
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