9/9—Local lockdowns outperform global lockdown
Here we develop a stochastic model […] parameterized with demographic, epidemiological, testing, and travel data from Ontario, Canada. We compare a local strategy of reopening (and reclosing, as needed) schools and workplaces county by county, according to triggers for county-specific infection prevalence, to a global strategy of province-wide reopening and reclosing, according to triggers for province-wide infection prevalence. For trigger levels that result in the same number of COVID-19 cases between the two strategies, the local strategy causes significantly fewer person-days of closure, even under high intercounty travel scenarios. However, both cases and person-days lost to closure rise when county triggers are not coordinated and when testing rates vary among counties (Karatayev et al. 2020).
Face Masks to Prevent COVID-19 in Community Settings
Evidence on the effectiveness of face masks to protect against COVID-19 in community settings were investigated in 12 studies. Five studies estimated a significant impact on the number of COVID-19 cases and fatalities due to mandatory face mask policies. Six retrospective epidemiological studies and one case control study based on contact tracing concluded that wearing a face mask by the index case or susceptible individuals was protective. Literature reviews mainly include evidence published prior to the COVID-19 pandemic. Randomized controlled trials (not on SARS-CoV-2) have not shown protective results. Observational studies of the protective effects of face masks against influenza like illness (ILI) were more significant.
Contact Tracing Assessment of COVID-19 Transmission Dynamics in Taiwan and Risk at Different Exposure Periods Before and After Symptom Onset
We enrolled 100 confirmed patients, with a median age of 44 years (range, 11-88 years), including 44 men and 56 women. Among their 2761 close contacts, there were 22 paired index-secondary cases. The overall secondary clinical attack rate was 0.7% (95% CI, 0.4%-1.0%). The attack rate was higher among the 1818 contacts whose exposure to index cases started within 5 days of symptom onset (1.0% [95% CI, 0.6%-1.6%]) compared with those who were exposed later (0 cases from 852 contacts; 95% CI, 0%-0.4%). The 299 contacts with exclusive presymptomatic exposures were also at risk (attack rate, 0.7% [95% CI, 0.2%-2.4%]). High transmissibility of COVID-19 before and immediately after symptom onset suggests that finding and isolating symptomatic patients alone may not suffice to contain the epidemic.
Aerosol and surface contamination of SARS-CoV-2 observed in quarantine and isolation care
During the initial isolation of 13 individuals with COVID-19 at the University of Nebraska Medical Center, we collected air and surface samples to examine viral shedding from isolated individuals. We detected viral contamination among all samples, supporting the use of airborne isolation precautions when caring for COVID-19 patients.
Comparison of Clinical Features of COVID-19 vs Seasonal Influenza A and B in US Children
In this cohort study of 315 US children with COVID-19 and 1402 children with seasonal influenza, there were no statistically significant differences in the rates of hospitalization, admission to the intensive care unit, and mechanical ventilator use between the 2 groups.
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