Daily profile of COVID-19 infections in Europe - a biophysical perspective

Progression of the European COVID-19 pandemic is monitored using daily cases and associated deaths, reported in Italy, Germany and England. Weekly periodicity in reporting is filtered out with a moving average over a 7-day window. This reveals underlying stages of exponential growth and decay, and changes in response to preventative interventions. Exponential rate constants $r_t$ , combined with different serial-interval distributions, yield estimates for the basic reproduction number R₀ and instantaneous R _t , and characterize the emergence of successive dominant viral variants. Rates of testing are discussed in detail, and corrected for. COVID-associated deaths are linked with daily cases, and fatality/case ratios (cfr) used to estimate the extent of under-reporting in the early stages. Reproduction numbers, R₀ and R _t , provide estimates of vaccine coverage required to reach population-level immunity, and subsequent modifications needed during the vaccination programme. Hence, we obtain a straightforward integrated description of the pandemic that is essentially biophysical.