Nowcasting and Forecasting the Spread of COVID-19 and Healthcare Demand In Turkey, A Modelling Study

Abdullah Ucar; Seyma Arslan; Muhammed Yusuf Ozdemir

There are various models developed to estimate and predict the course of epidemics in the literature. These models are generally classified under two groups as stochastic and deterministic. Depending on the developments in information technologies, simulations have been made recently with individual/agent-based models. (32) . One of the most frequently used models among deterministic models is the SEIR model, which is a compartment-based mathematical modeling type. In this model, the time between compartments is the basis of all estimates. In SEIR-based studies, generally, asymptomatic and symptomatic cases were not differentiated according to the incubation time, infectivity time, and R0 variables. In this study, these two groups are included in the model separately. The proportion of asymptomatic cases can be up to 78% in the studies performed according to the symptoms of the day the PCR sample was taken. (33, 34) . However, WHO stated that 75% of cases that were asymptomatic developed symptoms later and asymptomatic proportion is very low and is not a major determinant of the pandemic. (35) . In the study conducted on the Diamond Princess ship, 17.9% of all cases were stated to be asymptomatic. (20) . In our study, it was accepted that the closest study to the cohort design was Diamond Princess and this value was used in calculations.