Compact cities and the Covid-19 pandemic: Systematic review of the associations between transmission of Covid-19 or other respiratory viruses and population density or other features of neighbourhood design.

Living in compact neighbourhoods that are walkable, well connected, with accessible green space can benefit physical and mental health. However, the pandemic raises concern up to what extent features of compact neighbourhood design affect transmission of viral respiratory infections. We conducted a systematic review to identify, appraise and synthesise evidence reporting associations between transmission of respiratory viruses, including Covid-19, and dwelling or population density or other features of neighbourhood design. Twenty-one studies met our inclusion criteria. These studies used different measures of neighbourhood design, contributing to inconsistent findings. Whereas no convincing conclusion can be drawn here, the outcome of this review indicates that robust, global evidence is warranted to inform future policies and legislation concerned with compact neighbourhood design and transmission of respiratory and viral infection.

Lifestyle interventions for type 2 diabetes prevention in children and adolescents of African descent in OECD countries: a systematic review protocol.

OBJECTIVES: The objectives of this review are to investigate the effectiveness of lifestyle interventions for type 2 diabetes prevention in children and adolescents of African descent in the Organisation for Economic Co-operation and Development (OECD) member countries and to attempt to ascertain what aspects of these interventions are most effective in this population. INTRODUCTION: Lifestyle interventions have been shown to prevent or delay the onset of type 2 diabetes;however, the extent to which these interventions are effective for children and adolescents of African descent is not well established. The increasing type 2 diabetes incidence and prevalence in children and adolescents of African descent in some OECD member countries underscores the need to pool available evidence to ascertain the effectiveness of lifestyle interventions for type 2 diabetes prevention in this population. INCLUSION CRITERIA: Lifestyle interventions to be considered include individual-or group-based lifestyle or behavioral modification interventions aimed at preventing or delaying the onset of type 2 diabetes in children and adolescents of African descent aged 19 years and under in OECD countries. Randomized controlled trials and non-randomized studies that assess the effectiveness of lifestyle interventions for type 2 diabetes prevention will be considered. METHODS: The databases to be searched include MEDLINE, Embase, CINAHL, PsycINFO, Social Services Abstracts, Cochrane Central Register of Controlled Trials, and ProQuest Dissertations and Theses Global databases. There will be no language or date limits placed on the search. Two independent reviewers will conduct the title, abstract, and full-text screening, followed by critical appraisal and data extraction. Data will undergo meta-analysis where appropriate, and will otherwise be presented as narrative synthesis. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42021247267.

Which factors influence the extent of indoor transmission of SARS-CoV-2? A rapid evidence review.

BACKGROUND: This rapid evidence review identifies and integrates evidence from epidemiology, microbiology and fluid dynamics on the transmission of SARS-CoV-2 in indoor environments. METHODS: Searches were conducted in May 2020 in PubMed, medRxiv, arXiv, Scopus, WHO COVID-19 database, Compendex & Inspec. We included studies reporting data on any indoor setting except schools, any indoor activities and any potential means of transmission. Articles were screened by a single reviewer, with rejections assessed by a second reviewer. We used Joanna Briggs Institute and Critical Appraisal Skills Programme tools for evaluating epidemiological studies and developed bespoke tools for the evaluation of study types not covered by these instruments. Data extraction and quality assessment were conducted by a single reviewer. We conducted a meta-analysis of secondary attack rates in household transmission. Otherwise, data were synthesised narratively. RESULTS: We identified 1573 unique articles. After screening and quality assessment, fifty-eight articles were retained for analysis. Experimental evidence from fluid mechanics and microbiological studies demonstrates that aerosolised transmission is theoretically possible; however, we found no conclusive epidemiological evidence of this occurring. The evidence suggests that ventilation systems have the potential to decrease virus transmission near the source through dilution but to increase transmission further away from the source through dispersal. We found no evidence for faecal-oral transmission. Laboratory studies suggest that the virus survives for longer on smooth surfaces and at lower temperatures. Environmental sampling studies have recovered small amounts of viral RNA from a wide range of frequently touched objects and surfaces; however, epidemiological studies are inconclusive on the extent of fomite transmission. We found many examples of transmission in settings characterised by close and prolonged indoor contact. We estimate a pooled secondary attack rate within households of 11% (95% confidence interval (CI) = 9, 13). There were insufficient data to evaluate the transmission risks associated with specific activities. Workplace challenges related to poverty warrant further investigation as potential risk factors for workplace transmission. Fluid mechanics evidence on the physical properties of droplets generated by coughing, speaking and breathing reinforce the importance of maintaining 2 m social distance to reduce droplet transmission. CONCLUSIONS: This review provides a snap-shot of evidence on the transmission of SARS-CoV-2 in indoor environments from the early months of the pandemic. The overall quality of the evidence was low. As the quality and quantity of available evidence grows, it will be possible to reach firmer conclusions on the risk factors for and mechanisms of indoor transmission.