Result for
Topic: Transmission
May 21, 2021
Mask Use and Ventilation Improvements to Reduce COVID-19 Incidence in Elementary Schools — Georgia, November 16–December 11, 2020
An analysis of COVID-19 incidence in K-5 public schools in Georgia (N=169 schools, 91,893 students) found that incidence was 37% lower in schools that required teachers and staff to wear masks and 39% lower in schools that improved ventilation. Incorporating ventilation strategies to dilute airborne particles (opening windows and doors and/or using fans) was associated…
May 20, 2021
Characteristics of COVID-19 Cases and Outbreaks at Child Care Facilities — District of Columbia, July–December 2020
24% of 469 licensed childcare facilities in Washington, DC reported at least one SARS-CoV-2 infection from July to December 2020, but facility-associated outbreaks (defined as two or more linked cases within a facility) only occurred in 6% of facilities. Among the 316 total cases, 56% were among teachers or staff and 49% occurred during outbreaks….
May 19, 2021
SARS-CoV-2 Superspread in Fitness Center, Hong Kong, China, March 2021
A SARS-CoV-2 superspreading event in a fitness center in Hong Kong that resulted in 102 cases likely occurred due to lack of mask wearing during exercise and poor ventilation. The outbreak was detected following investigation of a fitness trainer who worked at the facility who tested positive in a voluntary screening program. 45% of cases…
May 18, 2021
Susceptibility and Infectiousness of Children and Adults with SARS-CoV-2 Variant B.1.1.7 Deduced from Three Daycare Centre Outbreaks and Related Household Situations Germany 2021
[Pre-print, not peer-reviewed] Secondary attack rates (SARs) were 17-37% in three kindergarten schools in Germany during three SARS-CoV-2 outbreaks likely caused by the B.1.1.7 variant. A majority (>80%) of secondary cases occurred within 7 days. The pooled household SAR was 37% after excluding single-occupant households and households with another possible index case. Notably, the attack…
Size and Duration of COVID-19 Clusters Go along with a High SARS-CoV-2 Viral Load: A Spatio-Temporal Investigation in Vaud State, Switzerland
Clustering of SARS-CoV-2 cases in Switzerland from January to June 2020 by region and date of diagnosis found that of the 457 clusters with significantly higher risk of infection compared to the surrounding region, 57% had at least one person with extremely high viral load (>1 billion copies/mL). Clusters with the highest viral loads tended…
Serial Interval of COVID-19 and the Effect of Variant B.1.1.7 Analyses from a Prospective Community Cohort Study (Virus Watch)
[Pre-print, not peer-reviewed] The mean interval between exposure to COVID-19 and the development of symptoms was 3.2 days, according to an analysis of 186 likely infector-infectee pairs in England and Wales. The mean serial interval in individuals belonging to households in regions and belonging to study weeks classified as having a high percentage of infections…
May 17, 2021
Asymptomatic SARS-CoV-2-Infected Children Attending Hospital with Non-COVID-19 Diagnoses, March 2020-February 2021
A surveillance study conducted between March 1, 2020 and February 21, 2021 in the UK found that out of 1,427 pediatric patients admitted to the hospital, 80 (5.6%) tested positive for SARS-CoV-2, of which 52 (65%) had symptoms compatible with COVID-19, 16 (20%) were asymptomatic, and 12 (15%) were “unclear” because of overlapping symptoms between…
May 12, 2021
SARS-CoV-2 Infectivity by Viral Load, S Gene Variants and Demographic Factors and the Utility of Lateral Flow Devices to Prevent Transmission
SARS-CoV-2 index cases with lower PCR cycle threshold (Ct) values (suggesting a higher viral load) tended to have a higher proportion of contacts infected with SARS-CoV2, according to a study combining testing and contact tracing data from England between September 2020 and February 2021. Attack rates were 12% for index cases with Ct=15 and 5%…
Household Overcrowding and Risk of SARS-CoV-2 Analysis of the Virus Watch Prospective Community Cohort Study in England and Wales
[Pre-print, not peer-reviewed] The proportion of people with SARS-CoV-2 positive PCR tests was higher among participants living in houses with more occupants than rooms (“overcrowded houses”) when compared to houses with fewer occupants (7% vs 3%) per room, according to a household community cohort study in England and Wales (n=10,33) conducted between June 2020 to…
May 11, 2021
Description of a University COVID-19 Outbreak and Interventions to Disrupt Transmission Wisconsin August – October 2020
[Pre-print, not peer-reviewed] Genomic surveillance of SARS-CoV-2 cases from Dane County, Wisconsin did not find evidence of onward community transmission from an outbreak at the University of Wisconsin (UW)-Madison that occurred during the first weeks of school reopening. During the outbreak, a large cluster of cases were identified in two residence halls, after which UW-Madison…
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