The COVID-19 epidemic, its mortality, and the role of non-pharmaceutical interventions.

Niel Hens,Geert Molenberghs,Pascal Vranck

doi:10.1177/2048872620924922

Abstract

COVID-19 has developed into a pandemic, hitting hard on our communities. As the pandemic continues to bring health and economic hardship, keeping mortality as low as possible will be the highest priority for individuals; hence governments must put in place measures to ameliorate the inevitable economic downturn. The course of an epidemic may be defined by a series of key factors. In the early stages of a new infectious disease outbreak, it is crucial to understand the transmission dynamics of the infection. The basic reproduction number (R0), which defines the mean number of secondary cases generated by one primary case when the population is largely susceptible to infection (‘totally naïve’), determines the overall number of people who are likely to be infected, or, more precisely, the area under the epidemic curve. Estimation of changes in transmission over time can provide insights into the epidemiological situation and identify whether outbreak control measures are having a measurable effect. For R0 > 1, the number infected tends to increase, and for R0 < 1, transmission dies out. Non-pharmaceutical strategies to handle the epidemic are sketched and based on current knowledge, the current situation is sketched and scenarios for the near future discussed.

Highlights

The world has not seen an epidemic that turned into a pandemic without adequate medicinal products since the H1N1 pandemic in 1918 (Spanish flu).[1,2]
The total volume of the epidemic will reduce, as the total fraction of infected population members is roughly equal to 1 – 1/ b, but a much more important effect is that the number of infected cases at any point in time remains below the capacity of the health care system
For the case fatality rate, figures around 5% have been quoted, some authors suggest much higher rates if longer time delays were to be taken into account.[25]

Summary

Introduction

The world has not seen an epidemic that turned into a pandemic without adequate medicinal products since the H1N1 pandemic in 1918 (Spanish flu).[1,2] There are important similarities as well as key differences. A key difference between COVID-19 and seasonal influenza is the very different reproduction number, b,9–11 a key quantity that, together with the recovery rate, k, drives the evolution over time of the susceptible, infected and recovered fractions, S(t), I(t) and R(t), respectively.

Results

Conclusion