  The non-equilibrium fluctuations observed in a number of COVID-19 cases and
deaths are analyzed from a statistical-dynamical point view. By investigating
the data observed around the world which were collected from January 15, 2020
to April 28, 2023 at https://coronavirus.jhu.edu/, we first show that the
dynamics of the fluctuations is described by a stochastic equation whose
stochastic force is a multiplicative type. By employing the
time-convolutionless projection-operator method in open systems previously
proposed by the present author, we then transform it into a Langevin-type
equation with an additive-type stochastic force together with the corresponding
Fokker-Planck type equation. Thus, we explore the stochastic properties of a
Langevin-type stochastic force not only analytically but also numerically from
a unified point of view. Finally, we emphasize that the dynamical behavior in
deaths resembles that in cases very much not only for the causal motion but
also for the fluctuation.
