Abstract

The box-shaped serial interval distribution and the analytical solution of the Susceptible Infectious-Recovered (SIR)-epidemics model with a constant time-independent ratio of the recovery ( ) to infection rate ( ) are used to calculate the effective reproduction factor and the basic reproduction number . The latter depends on the positively valued net infection number as which for all values of is greater unity. This dependence differs from the simple relation . With the earlier determination of the values of and of the Covid-19 pandemic waves in 71 countries the net infection rates and the basic reproduction numbers for these countries are calculated.