COVID-19 Literature Situation Report July 22, 2020

• Morely et al. compared daily estimates of Rt for 8 counties in central New York with publicly available data on measures of social distancing based on mobile phone data and found that the mean Rt dropped as the overall social distancing grade increased.  

Morley et al. (July 16, 2020). Social Distancing Metrics and Estimates of SARS-CoV-2 Transmission Rates. Journal of Public Health Management and Practice. https://doi.org/10.1097/PHH.0000000000001240 

• Analyzing 677 transmission pairs in mainland China, Ali et al. found that the COVID-19 serial interval, which is the time between symptom onset for the infector and the infectee in a linked transmission pair, shortened from 7.8 days to 2.6 days between Jan 9 and Feb 13.  The serial interval was positively associated with the length of time between a person’s symptom onset and their isolation (i.e. isolation delay). The investigators attribute these findings to the adoption of policies for rapid isolation of people with COVID-19 symptoms, and argue that changes in the serial interval indicate effective implementation of transmission reduction interventions.  

Ali et al. (July 21, 2020). Serial Interval of SARS-CoV-2 Was Shortened over Time by Nonpharmaceutical Interventions. Science. https://doi.org/10.1126/science.abc9004  

• After sampling environmental surfaces in the Diamond Princess cruise ship, Yamagishi et al. detected SARS-CoV-2 RNA from 10% of the samples from case-cabins 1-17 days after they were vacated and detected none in non-case-cabins. Asymptomatic and symptomatic case cabins had a similar proportion of detection (21% vs 15%). No viable SARS-CoV-2 virus was isolated from any of the samples. 

Yamagishi et al. (July 21, 2020). Environmental Sampling for Severe Acute Respiratory Syndrome Coronavirus 2 during COVID-19 Outbreak in the Diamond Princess Cruise Ship. The Journal of Infectious Diseases. https://doi.org/10.1093/infdis/jiaa437  

• Wu et al. tested wastewater collected at a major urban treatment facility in Massachusetts from March 18 to 25, 2020 and observed significantly higher SARS-CoV-2 titers (57 to 303 copies per mL of sewage) than expected based on number of clinically confirmed cases at the time. The investigators suggest that wastewater-based surveillance could help inform relaxing of lockdown and quarantine efforts. 

Wu et al. (July 21, 2020). SARS-CoV-2 Titers in Wastewater Are Higher than Expected from Clinically Confirmed Cases. MSystems. https://doi.org/10.1128/mSystems.00614-20  

• [Pre-print, not peer reviewed] The New York City Department of Health launched a SARS-CoV-2 cluster detection system using census tract resolution and the geospatial analysis software SaTScan. During June 11-30, 28 unique primary clusters were detected, highlighting the potential of spatiotemporal surveillance to support public health efforts. 

Greene et al. (July 21, 2020). Detecting Emerging COVID-19 Community Outbreaks at High Spatiotemporal Resolution – New York City June 2020. Pre-print downloaded July 22 from https://doi.org/10.1101/2020.07.18.20156901 

• A prospective cohort study (n=189) of COVID-19 patient in Iran showed that compared to the control group, participants receiving convalescent plasma therapy (n=115) had a significantly higher proportion of hospital discharge (98% vs 79%), shorter mean length of hospitalization (9.5 days vs 12.9 days), and lower proportion requiring intubation (7% vs 20%). 

Abolghasemi et al. (July 6, 2020). Clinical Efficacy of Convalescent Plasma for Treatment of COVID-19 Infections: Results of a Multicenter Clinical Study. Transfusion and Apheresis Science. https://doi.org/10.1016/j.transci.2020.102875 

• A systematic review (41 studies, 50,155 cases) found a pooled estimate that 16% of SARS-CoV-2 cases are asymptomatic across all age groups, with a higher percentage of asymptomatic children (28%). In a subset of initially asymptomatic patients (n=180) who were followed over time, 49% subsequently developed symptoms. The authors noted significant heterogeneity between study estimates of these measures. 

He et al. (July 21, 2020). Proportion of Asymptomatic Coronavirus Disease 2019 (COVID‐19): A Systematic Review and Meta‐analysis. Journal of Medical Virology. https://doi.org/10.1002/jmv.26326 

• Pierce et al. conducted a web survey of 17,452 people already participating in a UK national longitudinal study and found that population prevalence of clinically significant levels of mental distress rose from 19% in 2018-19 to 27% in April 2020, one month into the UK lockdown. Increases in individual scores on the GHQ-12, a questionnaire used to assess mental health, was greatest among young people (age 18-34), women, and people living with young children.  

Pierce et al. (July 2020). Mental Health before and during the COVID-19 Pandemic: A Longitudinal Probability Sample Survey of the UK Population. The Lancet Psychiatry. https://doi.org/10.1016/S2215-0366(20)30308-4  

• Using nationally a representative US sample  (n=34,653) from 2001-2002 and 2004-2005, Elbogen et al. found that cumulative financial strain was predictive of suicide attempts (OR = 1.53, 95%CI: 1.32, 1.77) and highlight the relevance of their findings given the financial strain triggered by the COVID-19 pandemic. 

Elbogen et al. (July 22, 2020). Financial Strain and Suicide Attempts in a Nationally Representative Sample of US Adults. American Journal of Epidemiology. https://doi.org/10.1093/aje/kwaa146 

• Cousins et al. found high correlation between regional confirmed case data from the New York Times and Google Trends results 10 days prior in most states (January 21 to April 2, 2020), suggesting that search-engine query patterns may be able to predict case activity while being robust to differences in regional location, population, and date of outbreak. 

Cousins et al. (July 19, 2020). Regional Infoveillance of COVID-19 Case Rates: Analysis of Search-Engine Query Patterns (Preprint). Journal of Medical Internet Research. https://doi.org/10.2196/19483 

• [Pre-print, not peer reviewed] Using an individual-based age-structured network model calibrated to a large city in Brazil (population: 300,000), Baumgartner et al. found that the model was more sensitive to interactions across different neighborhoods, suggesting that physical distancing at the city-level is more effective in controlling outbreaks and activities within the same neighborhood could only have minor contributions. 

Baumgartner and Lansac-Toha. (July 22, 2020). Assessing the Relative Contributions of Healthcare Protocols for Epidemic Control an Example with Network Transmission Model for COVID-19. Pre-print downloaded July 22 from https://doi.org/10.1101/2020.07.20.20158576 

• Wang et al. built a COVID-19 transmission model for Austin, TX incorporating age-stratified risks, contact patterns, and healthcare system factors and found that a 2 week delay in implementing extensive social distancing measures could accelerate the timing of peak healthcare needs by 4 weeks, causing shortages in beds and ICU units. School closures did not  affect the epidemic curve. 

Wang et al. (July 21, 2020). Impact of Social Distancing Measures on Coronavirus Disease Healthcare Demand, Central Texas, USA. Emerging Infectious Diseases. https://doi.org/10.3201/eid2610.201702