Result for
Topic: Transmission
November 3, 2020
SARS-CoV-2 Seroprevalence and Transmission Risk Factors among High-Risk Close Contacts: A Retrospective Cohort Study
A retrospective cohort study of all close contacts of confirmed COVID-19 cases in Singapore (n=7,770) found the attack rate among household contacts (5.9%) was higher compared to work contacts and social contacts (both 1.3%). Among contacts, close physical proximity (sharing a bedroom for household contacts and sharing a vehicle for work and social contacts) and…
November 2, 2020
Longitudinal Monitoring of SARS-CoV-2 RNA on High-Touch Surfaces in a Community Setting
[Pre-print, not peer-reviewed] A longitudinal study that sampled high-touch non-porous surfaces in Massachusetts during an outbreak of COVID-19 from April to June found the estimated risk of infection from touching a contaminated surface was less than 5 in 10,000, suggesting fomites play a minimal role in community spread. Overall, 29 (8.3%) of 348 surface swab…
Modeling the Load of SARS-CoV-2 Virus in Human Expelled Particles during Coughing and Speaking
A study using differential equations to describe the evolution of respiratory droplets, using SARS-CoV-2 as an example, found that there is no apparent size boundary between expelled particles that fall to the ground quickly versus those that can remain airborne. The simulation showed that after ten seconds of a cough, 5.1% of virus-containing particles were…
Viral Genome Sequencing Places White House COVID-19 Outbreak into Phylogenetic Context
[Pre-print, not peer-reviewed] Genomic sequencing indicated very close similarity between SARS-CoV-2 viruses isolated from two individuals who had separate exposures to the White House but did not share any other known exposures, indicating the White House events and/or personnel were the most likely source of both infections. While the authors conclude the White House was…
October 30, 2020
Transmission of SARS-COV-2 Infections in Households — Tennessee and Wisconsin, April–September 2020
A study of household SARS-CoV-2 transmission conducted in Tennessee and Wisconsin indicated that the secondary infection rate among household contacts overall was 53%, and that 75% of secondary infections occurred within 5 days of the onset of the index patient’s illness. Fewer than half of household members with confirmed SARS-CoV-2 infections reported symptoms at the…
Unravelling the Modes of Transmission of SARS-CoV-2 during a Nursing Home Outbreak: Looking beyond the Church Super-Spread Event
A March 2020 outbreak of SARS-CoV-2 in a nursing home in the Netherlands following a church service in the nursing home chapel revealed a complex chain of transmission involving the church service, regional circulation of the virus before the outbreak, and several introductions of the virus into the nursing home by visitors. The investigation indicated…
October 29, 2020
Optimal COVID-19 Quarantine and Testing Strategies
[Pre-print, not peer reviewed] A mathematical model found that a 13-day quarantine with testing on entry, a 9-day quarantine with testing on exit, and an 8-day quarantine with testing on entry and exit all provide equivalent or lower probability of post-quarantine transmission compared to a 14-day quarantine with no testing. When limited to a single…
COVID-19 Outbreak at an Overnight Summer School Retreat ― Wisconsin, July–August 2020
Investigation of a SARS-CoV-2 outbreak associated with an overnight high-school retreat suggests a single introduction from a student subsequently infected 76% (116) of attendees. The suspected index case received a negative PCR result 1 week prior to the retreat but experienced symptoms shortly after arrival. The attack rate among susceptible attendees was 91% (116 of…
October 28, 2020
COVID-19 Infections Following Physical School Reopening
[Pre-print, not peer reviewed] A study examining the effect of school re-opening on county-level COVID-19 incidence in Florida reported that counties with in-person instruction experienced a 16% increase in SARS-CoV-2 incidence at day 20 after school reopening among children age 6-13 years (from 11 to 12.8 per 100,000) and an increase of 27% among children…
COVID-19 Infections Following Outdoor Mass Gatherings in Low Incidence Areas Retrospective Cohort Study
[Pre-print, not peer reviewed] Among 20 counties in the US in which mass-gathering rallies associated with presidential campaigns were held (19 outdoor and 1 indoor) during August-September 2020, the COVID-19 incidence increased from 8.6 per 100,000 capita at the time of the gathering to 12.8 per 100,000 capita 15 days after the gathering (average of…
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