Update of the COVID-19 Incidence Forecast with the Overlap of Seasonal Flu Outbreaks

Introduction. The emergence of new vector-borne diseases necessitates the development of adequate medical regulations, prevention measures, rehabilitation programs, etc. Among all these measures, timeliness is the most crucial element, which cannot be achieved without reliable forecasting of the epidemic situation. In fact, the situation can deteriorate when two epidemics occur simultaneously, emphasizing the need for predicting the corresponding time intervals accurately. The aim of this study is to scientifically predict the periods when traditional influenza and COVID-19 epidemics may overlap. Materials and Methods. The scientific research was based on the analysis of statistical data, which was processed using Fourier decomposition and autoregression techniques to study and predict various processes. The original mathematical model of COVID-19 dynamics was adjusted with new statistical data. The resulting scale-time and random characteristics of COVID-19 within the model were compared with known parameters of traditional influenza. Results. It was established that the dynamics of the COVID-19 epidemic had a pronounced seasonal character with a frequency of three times a year. It was found that the method of forecasting COVID-19 incidence using Fourier decomposition was not reliable, but it allowed for a good description of the observed dynamics of the epidemic. Autoregressive analysis, on the other hand, was only suitable for short-term forecasting of coronavirus epidemics. The features of the two seasonal diseases, COVID-19 and influenza, have been compared, and the moments when their combined effects on a person would be particularly harmful have been predicted. Discussion and Conclusion. All methods of mathematical analysis have convincingly demonstrated that the frequency of COVID-19 outbreaks occurs three times per year, while influenza occurs annually. During times when the activities of both viruses (coronavirus and influenza) coincide, special attention should be paid and measures taken to reduce the risk of contracting a seasonal viral infection, including through regular vaccination.