COVID-19 and Spanish Flu Pandemics – Similarities and Differences

The aim of this paper is to analyze the similarities and differences between the COVID-19 and Spanish Flu and to predict the course of the COVID-19 pandemic. We carried out a literature search of publications in English in PubMed database with the following keywords: “COVID-19” and “Spanish Flu”. We found the following similarities between Spanish Flu and the COVID-19: the new agent, affected the whole world, similar reproductive numbers, similar case fatality rates, spreading through droplets or by touching contaminated surfaces, similar symptoms and signs, and middle-age as a dominant one among cases. The main differences are the causal agents, Spanish Flu started in the USA, while the COVID-19 started in China, currently, the number of cases and deaths was several times higher in Spanish Flu than in the COVID-19, and the incubation period is much longer in the COVID-19 (up to 28 days) than in Spanish Flu (1-2 days). Based on the experiences from Spanish Flu it may be expected that the COVID-19 pandemic may last until the end of 2021.