Voluntary measures to prevent Coronavirus infection were very effective
2 July 2020
Voluntary measures taken by individuals to reduce the spread of infection have been crucial in limiting the number of cases and deaths from COVID-19 in Sweden. This are the findings of a study in the scientific journal Clinical Infectious Diseases. Researchers have used a model that inputted with wide-ranging information about Sweden’s population.
Different countries have used varying strategies to limit the spread of COVID-19, and in international comparisons Sweden has stood out as a country with relatively moderate restrictions. Since the country’s strategy to limit the spread of the infection is largely based on recommendations from authorities, many people expected a large number of deaths in Sweden. But this worst-case scenario has not come to pass. Researchers at Uppsala University have used a computer model to explain why.
“When we initially modelled the effect of the restrictions from the Swedish Public Health Agency, we expected many more deaths and hospitalisations than what actually occurred. We can conclude that many people in Sweden have taken voluntary measures to limit the spread of the infection. These individual efforts have had a large effect and fundamentally changed the course of the pandemic in Sweden,” says Peter Kasson, senior lecturer at the Department of Cell and Molecular Biology at Uppsala University and Associate Professor at the University of Virginia.
Together with Lynn Kamerlin, professor at the Department of Chemistry at Uppsala University, he has used a computer model to account for each individual in Sweden to simulate how the disease spreads from person to person depending on individual social behaviour. This model predicted that the mandatory restrictions from the Public Health Agency alone would have little effect on the spread of the infection and lead to an overwhelmed health system. However, this did not turn out to be the case for Sweden.
When the model was adjusted to consider voluntary measures, the forecast aligned better with reality. To create a more accurate model that can explain a course of events is valuable even after the fact. It can be a tool in comparisons, analyses and reflections on what works well and what could have been done differently.
“We see that significant individual measures can work almost as well as an extensive shut down of society, if a large percentage of the population adopts the measures. Studies of the movement patterns of Swedes in the last few months indicate that at least a third of the population reduced its exposure to the virus at workplaces and in other social situations. This has had a large impact on the course of events,” says Lynn Kamerlin.
Access to intensive care beds in Sweden during the spring has been good and temporary field hospitals have remained unused. At the same time, the researchers behind the new study argue that society’s oldest generation may have paid a high price for this excessive capacity. The researchers have studied international data for survival of patients over 80 years of age that have received intensive care. They have also compared survival in this age group in Sweden with patients of the same age in the United States.
“Our data indicates that many patients 80 years and older were deprioritised even though their lives could have been saved if they had received access to intensive care,” says Peter Kasson.
S.C. Lynn Kamerlin and Peter M. Kasson (2020) Managing COVID-19 spread with voluntary public-health measures: Sweden as a case study for pandemic control, Clinical Infectious Diseases, DOI: 10.1093/cid/ciaa864