Abstract

Introduction: Models of kinetics of development of COVID-19 are essential for prognosis and preparedness of medical facilities for treating of patients.

Methods: We built a predictive model based on theoretical formulas for normal distribution and corrected it based on real number of cases in Latvia. The process included two stages: (I) simple modelling for distribution of cases without accounting for a state of emergency; (II) correction of the model for changes due to a state of emergency and a real situation. A choice of model parameters was performed comparing the real and the theoretical cumulative curves and based on the least sum of square. Considering in addition the tiredness of people to follow a state of emergency rules, we modelled the cumulative number of cases in Latvia till the end of 2020.

Result: The number of diseased cases in Latvia have Poisson distribution. According to our model, the best prediction is based on 7-14 days in which a carrier transmits the disease (p). After the declaration of a state of emergency the infection coefficient k decreased 3 to 5 times with fastest changes in incidence at day 50. The deviation from the theoretical curve as a result of violation of a state of emergency rules occurs at day 80. The cumulative number of cases in Latvia till the end of 2020 can reach 1400 in the case the current conditions will stay.

Conclusion: The provided model can be applied for other countries with similar distributions of cases.

Keywords: COVID-19; Low-incidence country; Latvia; Developmental kinetics