An agent-based epidemic model REINA for COVID-19 to identify destructive policies

Jouni T Tuomisto; Juha Yrjölä; Mikko Kolehmainen; Juhani Bonsdorff; Jami Pekkanen; Tero Tikkanen

In contrast, the mitigation policy allows the disease to spread in the society. The objective of the mitigation strategy is to slow down the epidemic rather than suppress it. The restrictions needed depend on the treatment capacity and how much the epidemic has to be slowed down to maintain the capacity. Unfortunately, both our modelling suggests and practical experiences from Italy, Spain, New York and elsewhere demonstrate that the capacity is very easily overwhelmed even if active restrictions are in place (Figure 7) . It is noteworthy that the mitigation strategy will lead to large health impacts irrespective of actions taken, because the strategy eventually allows the disease to spread widely, and a fraction of patients will have severe outcomes. Also, restrictions are needed for a long time until herd immunity slows down the epidemic, and side effects on daily life and the economy become large. Finally, our modelling of the mitigation strategy suggests that managing the appropriate level of restrictions would be very challenging due to the slow feedback and the potential for explosive exponential growth that characterise the COVID-19 epidemic.