Risk factors associated with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) transmission, outbreak duration, and mortality in acute-care settings.

BACKGROUND: Transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in acute-care settings affects patients, healthcare workers, and the healthcare system. We conducted an analysis of risk factors associated with outbreak severity to inform prevention strategies. METHODS: This cross-sectional analysis of COVID-19 outbreaks was conducted at Fraser Health acute-care sites between March 2020 and March 2021. Outbreak severity measures included COVID-19 attack rate, outbreak duration, and 30-day case mortality. Generalized linear models with generalized estimating equations were used for all outcome measures. A P value of 0.05 indicated statistical significance. Analyses were performed using SAS version 3.8 software, R version 4.1.0 software, and Stata version 16.0 software. RESULTS: Between March 2020 and March 2021, 54 COVID-19 outbreaks were declared in Fraser Health acute-care sites. Overall, a 10% increase in the hand hygiene rate during the outbreak resulted in an 18% decrease in the attack rate (P < .01), 1 fewer death (P = .03), and shorter outbreaks (P < .01). A 10-year increase in unit age was associated with 2.2 additional days of outbreak (P < 0.01) and increases in the attack rate (P < .05) and the number of deaths (P < .01). DISCUSSION: We observed an inverse relationship between increased hand hygiene compliance during outbreaks and all 3 severity measures. Increased unit age was also associated with increases in each of the severity measures. CONCLUSION: This study highlights the importance of hand hygiene practices during an outbreak and the difficulties faced by older facilities, many of which have infrastructural challenges. The latter reinforces the need to incorporate infection control standards into healthcare planning and construction.

Influencing dynamics on social networks without knowledge of network microstructure.

Social network-based information campaigns can be used for promoting beneficial health behaviours and mitigating polarization (e.g. regarding climate change or vaccines). Network-based intervention strategies typically rely on full knowledge of network structure. It is largely not possible or desirable to obtain population-level social network data due to availability and privacy issues. It is easier to obtain information about individuals' attributes (e.g. age, income), which are jointly informative of an individual's opinions and their social network position. We investigate strategies for influencing the system state in a statistical mechanics based model of opinion formation. Using synthetic and data-based examples we illustrate the advantages of implementing coarse-grained influence strategies on Ising models with modular structure in the presence of external fields. Our work provides a scalable methodology for influencing Ising systems on large graphs and the first exploration of the Ising influence problem in the presence of ambient (social) fields. By exploiting the observation that strong ambient fields can simplify control of networked dynamics, our findings open the possibility of efficiently computing and implementing public information campaigns using insights from social network theory without costly or invasive levels of data collection.

The Link Between Difficulty in Accessing Health Care and Health Status in a Canadian Context.

Much of the Canadian population reports some level of difficulty in accessing health care services. Despite being a recognized determinant of health, the relationship between access to health care and overall health has not been examined extensively. This study is an analysis of the Canadian Community Health Survey 2016 database. A composite score for difficulty in accessing health care was constructed based on several survey questions. Self-rated health (SRH), the measure of general health status, was compared between individuals with and without difficulty in accessing health care services by estimating prevalence rate ratios adjusting for age, sex, education, income, urban/rural status, race, and Indigenous status. After adjustment for pertinent confounders, difficulty in accessing health care was not statistically significantly associated with SRH. However, in stratified models, difficulty accessing health care was associated with a 12% lower probability of reporting good SRH among non-white individuals. Test of interactions for other social determinants was not significant. For racial minorities, inequalities in access to health care are associated with lower self-rated health. Further research to investigate causes underlying difficulties in accessing health care could lead to public health programs ensuring all Canadians receive equal health care services.

Effects of population growth on the success of invading mutants.

Understanding if and how mutants reach fixation in populations is an important question in evolutionary biology. We study the impact of population growth has on the success of mutants. To systematically understand the effects of growth we decouple competition from reproduction; competition follows a birth-death process and is governed by an evolutionary game, while growth is determined by an externally controlled branching rate. In stochastic simulations we find non-monotonic behaviour of the fixation probability of mutants as the speed of growth is varied; the right amount of growth can lead to a higher success rate. These results are observed in both coordination and coexistence game scenarios, and we find that the 'one-third law' for coordination games can break down in the presence of growth. We also propose a simplified description in terms of stochastic differential equations to approximate the individual-based model.