Projected effects of nonpharmaceutical public health interventions to prevent resurgence of SARS-CoV-2 transmission in Canada

Abstract

BACKGROUND: Continual efforts to eliminate community transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will be needed to prevent additional waves of infection. We explored the impact of nonpharmaceutical interventions on projected SARS-CoV-2 transmission in Canada. METHODS: We developed an agestructured agent-based model of the Canadian population simulating the impact of current and projected levels of public health interventions on SARS-CoV-2 transmission. Interventions included case detection and isolation, contact tracing and quarantine, physical distancing and community closures, evaluated alone and in combination. RESULTS: 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 INTERPRETATION: Controlling SARS-CoV-2 transmission will depend on enhancing and maintaining interventions at both the community and individual levels. Without such interventions, a resurgent epidemic will occur, with the risk of overwhelming our health care systems.

Predictors of attitudes and adherence to COVID-19 public health guidelines in Western countries: a rapid review of the emerging literature

“… 1–3 Recent predictive modelling from Canada estimates that without the implementation of public health measures, 64.6% of the population would become infected with COVID-19, and ~3.6% of those infected would die from COVID-19 related illness by January 2022. 4 Behavioral public health measures are crucial to curb infection rates as no curative treatment for COVID-19 is currently available and it is unclear in many jurisdictions when approved vaccines will be widely available to the general population. 5 As such, some form of these protective behaviors may be required into 2022, with risk of pandemic resurgence remaining elevated into 2024.…”

Shaping the future of the COVID-19 pandemic in Canada

“…Ng and colleagues also show that achieving elimination of SARS-CoV-2 without restrictive measures is unlikely. 1 The term "elimination" in public health refers to the reduction of incidence of infection caused by a specific pathogen to zero in a defined geographical region. 7 As long as transmission occurs outside of the region that is aiming for elimination, risk of reintroduction remains.…”

“…Mathematical modelling can help to guide policy-makers in working out what is required to achieve epidemic control. As Ng and colleagues show, 1 combinations of interventions are likely to be more effective than single public health measures, particularly as communities move away from large-scale closures of schools and workplaces. But the effectiveness of different interventions for reducing transmission is only one piece of the puzzle.…”

“…Ng and colleagues' model has a lengthy time horizon (January 2022), and even the limited scenarios that can lead to elimination of COVID-19 often achieve this only after they have been in place for more than a year. 1 There is no single correct path forward in this pandemic. Policymakers need to determine how to strategically use public health measures to achieve improved epidemic control and determine whether there are aspects of the initial pandemic response that require additional investment and resources.…”

Trouver, tester, « tracer » et isoler énergiquement pour battre la COVID-19

“…Deuxièmement, étant donné que les personnes infectées asympto matiques contribuent aussi et significativement à la propagation du SRAS-CoV-2 2 , les campagnes de la santé publique doivent continuer de marteler ses consignes sur le lavage des mains, le port du couvre-visage, la distanciation physique et le respect des petites bulles so ciales. Les personnes asymptomatiques qui sont infectées par le SRAS-CoV-2 doivent aussi être identifiées pour pouvoir s'isoler avant de propager le virus 3,4 . Mais parmi les personnes asymptomatiques, lesquelles sont les plus susceptibles d'avoir contracté le SRAS-CoV-2 5 ?…”