Simulations of the pandemic propagation patterns on the example of Poland and Ukraine

The aim of Chapter 6 is to provide possible scenarios of the pandemic propagation in Poland and Ukraine depending on the actions taken by the government aiming to introduce restrictions on socio-economic life, the so-called lockdown. The scenario analysis was based on an extended version of the SIR (Susceptible–Infected–Removed) model. In the first scenario (A), the lockdown is to be lifted when the proportion of infected individuals falls below 50% of the actual proportion on day 275 of the epidemic. In scenario B restrictions are to be lifted gradually over a month, and in the final scenario (C) all restrictions are to be lifted on a specific day in 2021. In addition, each scenario includes variants without vaccination and with a vaccination programme. The results of the scenario analysis indicate that, both in Poland and in Ukraine, the best results in terms of the number of deaths and the number of people infected at the peak of the epidemic can be achieved in Scenario A with vaccination. In Poland, the proportion of deaths in this scenario varies between 3.0-4.1‰ of the population, and the proportion of infected individuals during the peak is about 1.2%. In Ukraine, on the other hand, under scenario A, the proportion of deaths varies between 2.8-3.7‰ and the proportion of infected individuals during the peak is 1.35-1.4%. Both in Poland and in Ukraine, the highest proportion of deaths would be observed in scenarios C and B without vaccination programmes, respectively 7.5-7.9‰ for Poland and 8.1-8.2‰ for Ukraine. According to these scenarios, at the peak of the epidemic 3.7-3.8% of the population would be infected in Poland and 4.4-4.7% in Ukraine.