Investigating duration and intensity of Covid-19 social-distancing strategies

Abstract

The exponential character of the recent Covid-19 outbreak requires a change in strategy from containment to mitigation. Meanwhile, most countries apply social distancing with the objective to keep the number of critical cases below the capabilities of the health care system. Due to the novelty and rapid spread of the virus, an a priori assessment of this strategy was not possible. In this study, we present a model-based systems analysis to assess the effectiveness of social distancing measures in terms of intensity and duration of application. Results show a super-linear scaling between intensity (percent contact reduction) and required duration of application to have an added value (lower fatality rate). This holds true for an effective reproduction of R > 1 and is reverted for R < 1. If R is not reduced below 1, secondary effects of required long-term isolation are likely to unravel the added value of disease mitigation. If an extinction is not feasible, we recommend moderate social-distancing that is well balanced against capability limits of national health-care systems.2 COVID-19 cases is above 2.5 million resulting in over 170,000 deaths [1]. Due to these 3 large numbers, the initial approach of containment, i.e. tracing contacts of patients with 4 laboratory-confirmed infection [2], is not applicable anymore and may even have 5 unintended consequences of hampering effective healthcare delivery [3]. Instead, the 6 majority of countries decided to use community interventions, like cancellation of events, 7 general social distancing and travel restrictions [4].8These community mitigation measures reduce transmission, hence flatten the curve 9 and push the peak of new infections further into the future which eventually helps 10 preventing an epidemic peak that overwhelms health-care systems [5]. Numerous 11 studies support this strategy [3] [4] [6] [7]. There is no doubt that this is the right 12 course of action to protect the lives of many vulnerable patients. Nevertheless, 13 considering the basic reproduction of Covid-19 as well as the considerable variation of 14 regional availability of intensive care [8], drastic interventions are needed to push new 15infections below the maximum capabilities of national health care systems. This is also 16 evident from the actions taken by European countries who implemented interventions

Exploring Knowledge, Prevention Methods, and Prevention Barriers of COVID-19 Among Somali, Karen, and Latinx Community Members in Minneapolis, Minnesota, USA

“…24 Research has demonstrated that the most effective strategy to prevent infection by COVID-19 is social distancing. 25 The ability to socially distance while working from home and telecommuting are issues of privilege. 26 As noted in the interviews, social distancing does not accommodate high occupancy housing or essential workers who are continuing to work in the community and risking transmission back at home.…”

Covid-19 social distancing: when less is more

“…Limiting social contacts over the long term may, however, be undermined by the previouslymentioned negative societal and economic effects associated with strictly enforced social contact reduction and isolation. As shown in a previous exploratory study (Neuwirth et al, 2020), if social distancing cannot be sustained over a sufficient length of time (i.e. from outbreak until vaccination and herd immunity), a large second wave of outbreaks can negate the mitigating effects of previously imposed restrictions.…”

“…The Covid-19 outbreaks in Slovenia and Austria were modeled using the same compartmental model that was used in a previous exploratory investigation into Covid-19 and social distancing (Neuwirth et al, 2020). In order to address the large number of asymptomatic infections (Gao et al, 2020;Mizumoto et al, 2020), as well as potential increases in case fatality rates due to an excess demand for health facilities (Rajgor et al, 2020;Remuzzi & Remuzzi, 2020), the model extends the standard SIR (susceptible-infected-resistant) model and includes the following compartments: susceptible 𝑆(𝑡), infected -infection unknown 𝐼(𝑡), infected in isolation 𝐼𝐼(𝑡), resistant symptomatic 𝑅𝑆(𝑡), resistant asymptomatic 𝑅𝐴(𝑡), deaths 𝐷(𝑡), deaths caused by denied ICU treatment 𝐷𝐿(𝑡).…”