COVID-19 healthcare demand and mortality in Sweden in response to non-pharmaceutical mitigation and suppression scenarios

Abstract

Background: While the COVID-19 outbreak in China now appears suppressed, Europe and the USA have become the epicentres, both reporting many more deaths than China. Responding to the pandemic, Sweden has taken a different approach aiming to mitigate, not suppress, community transmission, by using physical distancing without lockdowns. Here we contrast the consequences of different responses to COVID-19 within Sweden, the resulting demand for care, intensive care, the death tolls and the associated direct healthcare related costs.

Methods: We used an age-stratified health-care demand extended SEIR (susceptible, exposed, infectious, recovered) compartmental model for all municipalities in Sweden, and a radiation model for describing inter-municipality mobility. The model was calibrated against data from municipalities in the Stockholm healthcare region.

Results: Our scenario with moderate to strong physical distancing describes well the observed health demand and deaths in Sweden up to the end of May 2020. In this scenario, the intensive care unit (ICU) demand reaches the pre-pandemic maximum capacity just above 500 beds. In the counterfactual scenario, the ICU demand is estimated to reach ∼20 times higher than the pre-pandemic ICU capacity. The different scenarios show quite different death tolls up to 1 September, ranging from 5000 to 41 000, excluding deaths potentially caused by ICU shortage. Additionally, our statistical analysis of all causes excess mortality indicates that the number of deaths attributable to COVID-19 could be increased by 40% (95% confidence interval: 0.24, 0.57).

Conclusion: The results of this study highlight the impact of different combinations of non-pharmaceutical interventions, especially moderate physical distancing in combination with more effective isolation of infectious individuals, on reducing deaths, health demands and lowering healthcare costs. In less effective mitigation scenarios, the demand on ICU beds would rapidly exceed capacity, showing the tight interconnection between the healthcare demand and physical distancing in the society. These findings have relevance for Swedish policy and response to the COVID-19 pandemic and illustrate the importance of maintaining the level of physical distancing for a longer period beyond the study period to suppress or mitigate the impacts from the pandemic.

Keywords: COVID-19; SARS-CoV-2; Sweden; care demand; corona virus; deaths; epidemic; epidemiology; excess mortality; infections; intensive care demand; mortality; outbreak; pandemic.

Figure 1

Predicted number of total deaths from COVID-19 in the whole population in Sweden (first column), and for Stockholm region (second column); predicted demand of ICU beds in Stockholm (third column), and; inpatient care beds in Stockholm (fourth column). Actual observations in the early phase of the outbreak are illustrated as circles (O). The scenarios are organized in rows with panel (a) no public health interventions (counterfactual scenario); (b) modest physical distancing in ages 0–59 years, moderate in ages 60+ years; (c) modest physical distancing in ages 0–59 years, moderately strong in ages 60+ years; (d) moderate physical distancing in ages 0–59 years, very strong in ages 60–79 years, strong in ages 80+ years, and with an increased degree of isolation of infectious individuals; (e) moderate physical distancing in ages 0–59 years, strong in ages 60+ years, and further improved isolation of infectious individuals. Mitigation giving rise to these predicted values had onset the 20th of March.

Figure 2

Top panel (a) The number of individuals in the Stockholm region predicted to carry the virus over time as determined by a virus detection assay. The empirical measurement from April 1st, 2020, using a population sample, is illustrated by a circle (O) with 95% CI (vertical bars); Bottom Panel (b) The cumulative number of predicted infected people detected in an antibody test by the end of April (assuming antibodies cannot be not detected immediately. The scenarios are organized in rows with panel (a) no public health interventions (counterfactual scenario); (b) modest physical distancing in ages 0–59 years, moderate in ages 60+ years; (c) modest physical distancing in ages 0–59 years, moderately strong in ages 60+ years; (d) moderate physical distancing in ages 0–59 years, very strong in ages 60–79 years, strong in ages 80+ years, and with an increased degree of isolation of infectious individuals; (e) moderate physical distancing in ages 0–59 years, strong in ages 60+ years, and further improved isolation of infectious individuals. Mitigation giving rise to these predicted values had onset the 20th of March.

Figure 3

The predicted ICU bed demand per day from 24th of February to the 1st of September, 2020, overall in Sweden in relation to different suppression & mitigation scenarios. The scenarios are organized in rows with panel (a) no public health interventions (counterfactual scenario); (b) modest physical distancing in ages 0–59 years, moderate in ages 60+ years; (c) modest physical distancing in ages 0–59 years, moderately strong in ages 60+ years; (d) moderate physical distancing in ages 0–59 years, very strong in ages 60–79 years, strong in ages 80+ years, and with an increased degree of isolation of infectious individuals; (e) moderate physical distancing in ages 0–59 years, strong in ages 60+ years, and further improved isolation of infectious individuals. Mitigation giving rise to these predicted values had onset the 20th of March.

Figure 4

The predicted ICU bed demand per day from 24th of February to the 1st of September, 2020, in the region of Stockholm in relation to different suppression & mitigation scenarios. The scenarios are organized in rows with panel (a) no public health interventions (counterfactual scenario); (b) modest physical distancing in ages 0–59 years, moderate in ages 60+ years; (c) modest physical distancing in ages 0–59 years, moderately strong in ages 60+ years; (d) moderate physical distancing in ages 0–59 years, very strong in ages 60–79 years, strong in ages 80+ years, and with an increased degree of isolation of infectious individuals; (e) moderate physical distancing in ages 0–59 years, strong in ages 60+ years, and further improved isolation of infectious individuals. Mitigation giving rise to these predicted values had onset the 20th of March.