Image: Jussi Nukari / Lehtikuva

Significantly relaxing current social distancing restrictions could lead to an explosion of coronavirus cases in Finland and the overburdening of the healthcare system, according to a model developed by a group of Finnish researchers.

However they said better testing and contact tracing could go a long way toward reducing the severity of the outbreak.

The new model presents a much gloomier outlook than projections put forward by the Finnish Institute of Health and Welfare, THL, estimates.

The research group's model predicts that if restrictions are relaxed, more than half of Uusimaa residents would be infected, and some 6,000 people -- nearly one percent of those infected -- could die. Elsewhere in Finland, the mortality rate could be even higher.

THL's latest modelling estimates mortality in Finland at 0.2 percent, according to THL expert Jussi Sane.

The new model is designed by a group of independent researchers from the Universities of Helsinki and Eastern Finland as well as software developers, but THL researcher Jouni Tuomisto is also part of the team.

Their goal was to create a simulation model that would allow Finland's political leadership to make decisions about coronavirus measures.

The message in a nutshell: don't relax yet.

"I would not recommend thinking that we have seen the worst yet," Tuomisto said.

Slowdown not sufficient

According to the researchers' simulation Reina (Realistic Epidemic Interaction Network Agent Model), there is a possibility that the coronavirus epidemic could be worse in Finland than it was in Italy.

The team has broken Finland's possible responses into two alternatives: either Finland will attempt to slow the spread of the virus or stop it altogether.

The modelling can be viewed on the project website here.

If the aim is to slow down the epidemic, infections will inevitably continue to spread. In such a case, according to the simulation, the virus could kill 6,000 people in Uusimaa alone and a huge number in Finland within a year.

Another alternative is to stop the epidemic with drastic action. In this scenario, current restrictions will continue and contact tracing will be much better than it is now.

In such a case, the epidemic would subside by autumn and the number of deaths in Uusimaa, for example, could be around 600, according to the simulation. That would be a tenth of what the death tool could be if restrictions are eased.

Regardless of which path Finland chooses, coronavirus is here to stay, according to the researchers. Even if the epidemic was brought to a near halt, it could still erupt again later, depending on the restrictions in force at the time.

Tuomisto and his fellow-researchers worked on the model for months and published it on Tuesday. There is no peer review of the model yet.

Situation can spiral out of control

Researchers estimate that current restrictions on social contact have reduced the number of possible infections to half of what it could have been with pre-pandemic levels of contact. If contact levels continue to be limited for six months, the epidemic would subside in October, the model suggests.

However, Tuomisto does not believe that it will be possible to maintain current restrictions for the next six months.

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Image: Harri Vähäkangas / Yle

"I have not heard from anyone that the current restrictions will be maintained for six months. That would cause a terrible economic storm," Tuomisto said.

The Ministry of Finance estimated on Thursday that measures to restrict the economy would last only three months altogether. Relaxing the restrictions could prove very costly, according to Tuomisto.

"The epidemic could get out of control and the situation can easily be ten times worse," Tuomisto warns.

If the reduction in close contact will be 30 percent and not 50 percent compared to pre-pandemic times, the epidemic would sweep across the region over the course of the year.

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Image: Harri Vähäkangas / Yle

According to Tuomisto, it is not yet known what kind of outcome an uncontrolled epidemic could cause in Finland.

"That situation could be two times worse than it is in Italy now. There is good reason to assume that such a situation can occur in Finland if the disease is allowed to spread freely," Tuomisto says.

Interactive model simulates outcomes

The scenarios were developed using data from the 1.6-million-resident Helsinki and Uusimaa Hospital District (HUS) as the model.

Tuomas Aivelo, an ecologist and evolutionary biologist from the University of Helsinki estimated that the fundamental assumptions of the research group's new model are realistic. In practice, the model is almost the same as the model used by London's Imperial College to simulate a pandemic and to advise the UK government.

"The assumptions are the best in scientific literature," Aivelo said.

Anyone can experiment and adjust the basic assumptions of the open-source epidemic model Reina, and also track the impact of the changes on the course of the epidemic. This can be used to test, for example, how easing restrictions in the summer would affect the outbreak.

According to the model, a scenario called ‘summer easing’ would, for instance, lead to an overburdening os intensive care capacity for more than three months. At the same time, the number of deaths would increase more than 60 times compared to the scenario where the current restrictions are in place for another six months.

Finland picks middle ground

According to researchers, Finland is now at a crossroads. The epidemic may be reined in or it may explode out of control. In order to stop the epidemic, efforts should be made to find and isolate asymptomatic virus carriers to trace the chains of infection.

"All other options lead to the disease getting out of hand sooner or later," Tuomisto said.

Researchers say large-scale testing alone would reduce deaths by about 75 percent. Combined with contact tracing, fatalities could be reduced by 92 percent.

According to the model, authorities will not bring the epidemic under control without extending current distancing measures to six months or introducing large-scale testing and contact tracing.

The study emphasises that large-scale testing would enable restrictions to be targeted correctly, allowing a large proportion of Finns to return to a slightly more normal life. When only carriers are isolated from others, restrictions on movement do not have to be applied indiscriminately to everyone, reducing the impact of economic losses on the rest of society.

The researchers observed that the Finish approach lies somewhere between slowing down and stopping the epidemic.

"The hybrid model tries to minimise the number of cases by increasing testing as much as possible and trying to trace contact chains," Tuomisto commented.

However, he pointed out that he has no influence on THL's approach to managing the epidemic.