Kamerlin SCL, Kasson PM. Managing COVID-19 spread with voluntary public-health measures: Sweden as a case study for pandemic control [published online ahead of print, 2020 Jul 1]. Clin Infect Dis. 2020;ciaa864. doi:10.1093/cid/ciaa864
Background: The COVID-19 pandemic has spread globally, causing extensive illness and mortality. In advance of effective antiviral therapies, countries have applied different public-health strategies to control spread and manage healthcare need. Sweden has taken a unique approach of not implementing strict closures, instead urging personal responsibility. We analyze the results of this and other potential strategies for pandemic control in Sweden.
Methods: We implemented individual-based modeling of COVID-19 spread in Sweden using population, employment, and household data. Epidemiological parameters for COVID-19 were validated on a limited date range; where substantial uncertainties remained, multiple parameters were tested. The effects of different public-health strategies were tested over a 160-day period, analyzed for their effects on ICU demand and death rate, and compared to Swedish data for April 2020.
Results: Swedish mortality rates fall intermediate between European countries that quickly imposed stringent public-health controls and countries that acted later. Models most closely reproducing reported mortality data suggest large portions of the population voluntarily self-isolate. Swedish ICU utilization rates remained lower than predicted, but a large fraction of deaths occurred in non-ICU patients. This suggests that patient prognosis was considered in ICU admission, reducing healthcare load at a cost of decreased survival in patients not admitted.
Conclusions: The Swedish COVID-19 strategy has thus far yielded a striking result: mild mandates overlaid with voluntary measures can achieve results highly similar to late-onset stringent mandates. However, this policy causes more healthcare demand and mortality than early stringent control and depends on continued public will.