Scientists of Igor Sikorsky Kyiv Polytechnic Institute and the Gromashevsky Institute of Epidemiology and Infectious Diseases executed study of the spread of the fourth wave of COVID-19, caused by the strain "Delta", in Ukraine and the countries of the world that have felt the greatest impact of the pandemic. The pandemics of severe acute respiratory syndrome, swine flu, Ebola, and COVID-19 over a five- to six-year period have been found to occur over the past 20 years.
Using the methods of technical analysis of large data also revealed the cyclical nature of the flow of four waves of the COVID-19 pandemic process over time: January 2020 - September 2021. The results indicate a significantly lower level of new disease and mortality during the current fourth wave of the pandemic process, compared to the second and third waves, in countries with a high percentage of vaccinated population.
The clustering of the countries of the world according to the main signs of the spread of the disease, the rate of vaccination and the rate of extinction of the pandemic was performed. Ukraine has entered the group of countries in which the new wave has not yet reached its maximum. In September 2021, mortality in Ukraine is growing faster than during the same period in 2020. As of mid-September 2021, the country has a low level of fully vaccinated population (about 12%) and therefore may face severe consequences of the pandemic in the near future.
The researchers believe that because the number of hospitalizations and mortality are key determinants, it is important to vaccinate the most vulnerable COVID-19 groups, the age group 60 and older, and those with comorbidities.
Forecasting the dynamics of the new, fourth wave of COVID-19 in Ukraine 200 days ahead using the method of comparative analysis and neural network such as "direct perceptron" showed that this wave is growing, it may be faster, but shorter than the previous ones. Its peak is estimated at 15,000-18,000 cases per day. The fading of the fourth wave is expected at the end of 2021.
An important predictor of such a complication of the epidemic situation with COVID-19 is a significant easing of quarantine restrictions in the summer, and in most educational institutions - from early September. In addition, the probability of seasonal increase in other respiratory infections, the intensity of the epidemic process of which during the previous 1.5 years was constrained by quarantine and other anti-epidemic restrictions, should be taken into account.