8/20—SARS-CoV-2 viral load predicts COVID-19 mortality

PCR allows for calculation of viral load, which is associated with transmission risk and disease severity in other viral illnesses. To our knowledge, we are the first to report on SARS-CoV-2 viral load at diagnosis as an independent predictor of mortality in a large hospitalised cohort (n=1145). A Cox proportional hazards model adjusting for age, sex, asthma, atrial fibrillation, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, diabetes, heart failure, hypertension, stroke, and race yielded a significant independent association between viral load and mortality (hazard ratio 1·07 [95% CI 1·03–1·11], p=0·0014), with a 7% increase in hazard for each log transformed copy per mL (Pujadas et al. 2020).

Cluster infections play important roles in the rapid evolution of COVID-19 transmission: a systematic review
A total of 65 studies were included in this study which involved 108 cluster infections from 13 countries, areas or territories. The major types of clusters are family cluster (62), in community (4), nosocomial infection (3), transmission in gathering activities (15), on transportations (6), in shopping malls (3), on conference (4), during tourists (6), and in religious organizations (5).

Automated and partly automated contact tracing: a systematic review to inform the control of COVID-19
Of the 4036 studies identified, 110 full-text studies were reviewed and 15 studies were included in the final analysis and quality assessment. No empirical evidence of the effectiveness of automated contact tracing (regarding contacts identified or transmission reduction) was identified. Four of seven included modelling studies that suggested that controlling COVID-19 requires a high population uptake of automated contact-tracing apps (estimates from 56% to 95%). Studies of partly automated contact tracing generally reported more complete contact identification and follow-up compared with manual systems. Automated contact tracing could potentially reduce transmission with sufficient population uptake.

Social Distancing and Public Health Guidelines at Workplaces in Korea: Responses to Coronavirus Disease-19
When the first confirmed case was diagnosed, [Korea CDC] responded quickly, emphasizing early detection with numerous tests and a social distancing policy. This slowed the spread of infection without intensive containment, shut down, or mitigation interventions. After entering the public health blue alert level, a business continuity plan was distributed. After entering the orange level, the Ministry of Employment and Labor developed workplace guidelines for COVID-19 consisting of social distancing, flexible working schedules, early identification of workers with suspected infections, and disinfection of workplaces. Owing to the intensive workplace social distancing policy, workplaces remained safe with only small sporadic group infections. By May 15, 2020, 11,018 COVID-19 cases were identified.

Projected effects of nonpharmaceutical public health interventions to prevent resurgence of SARS-CoV-2 transmission in Canada
Without any interventions, 64.6% (95% credible interval [CrI] 63.9%–65.0%) of Canadians will be infected with SARS-CoV-2 (total attack rate) and 3.6% (95% CrI 2.4%–3.8%) of those infected and symptomatic will die. If case detection and contact tracing continued at baseline levels without maintained physical distancing and reimplementation of restrictive measures, this combination brought the total attack rate to 56.1% (95% CrI 0.05%–57.1%), but it dropped to 0.4% (95% CrI 0.03%–23.5%) with enhanced case detection and contact tracing. Combining the latter scenario with maintained physical distancing reduced the total attack rate to 0.2% (95% CrI 0.03%–1.7%) and was the only scenario that consistently kept hospital and intensive care unit bed use under capacity, prevented nearly all deaths and eliminated the epidemic. Extending school closures had minimal effects but did reduce transmission in schools; however, extending closures of workplaces and mixed-age venues markedly reduced attack rates and usually or always eliminated the epidemic under any scenario.

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