ESTIMATION OF THE VALUE OF THE COVID-19 BASIC REPRODUCTIVE NUMBER AND THE EFFECT OF ANTI-EPIDEMIC MEASURES AND “SEASONAL FACTOR” ON THIS VALUE

Background: The emergence of COVID-19 has led to increased attention to mathematical models of epidemiology, one of the main parameters of which is the basic reproductive number R0. Its value determines both the dynamics of the incidence and the level of anti-epidemic measures. Therefore, it is desirable to have a fairly accurate method for assessing R0 for each day. Aim: Develop a methodology for determining the R0 value for COVID-19, taking into account a reasonably rapid and significant change in its value over time. Methods: a method for calculating reproduction number R0 was proposed for assessing COVID-19 R0, taking into account the change in the contagiousness of the infected people during the infectious process. Results and Discussion: In Russia in June-August 2020, the reproduction rate was slightly less 1, but in September R0 began to grow, exceeded 1, which was caused a noticeable increase in the incidence. During June in Brazil, R0 stabilized at a value of 1. The activity of transmission of the pathogen is influenced by seasonal changes in the reproduction rate R0 and the level of community immune status. Based on the assessment of the dynamics of the incidence of other pneumonia, it was found that the change of R0 during the year is about 10%, with a minimum in summer. Conclusions: while maintaining the current activity of anti-epidemic measures due to seasonal factors of the activity of the transmission mechanism and accumulation of the immune individuals in the coming months, the situation in the Russian Federation will worsen with an increase in the incidence doubled within six months, and in Brazil in six months — improve with a decrease in the incidence ten times. However, the dynamics of the incidence will be determined primarily by the work of the administration and health authorities and the conscientiousness of citizens.