The Future of the COVID-19 Pandemic: Insights from the Human Coronaviruses Found before 2019

Abstract

At the end of December 2019, epidemic cases of pneumonia of unknown cause in Wuhan, China were reported to the World Health Organization (WHO). A novel species of coronavirus was identified as the causative agent and named SARS coronavirus type 2 (SARS-CoV-2) because its genome sequence was found to be similar to that of SARS coronavirus (SARS-CoV), which caused the outbreak of severe acute respiratory syndrome (SARS) from 2002 to 2003. The WHO has designated the official name of SARS-CoV-2 infection as coronavirus disease 2019 (COVID-19) and declared it a pandemic on March 11, 2020. As of this writing (March, 2022), there are about 480 million people who have been infected with SARS-CoV-2 and more than 6 million killed worldwide, and the pandemic is inflicting a huge negative impact on various aspects of human life. Six species of coronavirus, which cause human diseases, had been identified before the outbreak of COVID-19. Four of them cause the common cold, and the other two cause severe respiratory disease with high case fatality rates. In this paper, the possible origins and phylogenetic properties of these human coronaviruses are summarized, and the future of the COVID-19 pandemic will be speculated based on the characteristics of pre-existing human coronaviruses.