COVID-19 is a newly discovered, highly infectious disease and has rapidly spread into at least 213 countries as a pandemic. This paper is a comprehensive review article of COVID-19 and four other viral diseases, including influenza, Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and Ebola virus disease (EVD). The cause of COVID-19 is the novel coronavirus—SARS-CoV-2. The transmission of COVID-19 is complex and rapid; therefore, it is difficult to control the spread of the disease. Certified specific antiviral drugs are slowly becoming available for COVID-19, although a few treatments such as Remdesivir, hydroxychloroquine, dexamethasone, and therapeutic plasma exchange (TPE) have been found somewhat effective. Effective vaccines are still in the process of development and several countries, including the USA are conducting Phase 3 trials currently to fast-track the vaccines. All these issues have created significant challenges in reducing the morbidity and mortality of this global infectious disease. COVID-19 has led to vast impacts on public health and the global economy. With economic shutdowns, social distancing, increased handwashing, and sanitizing have been first line therapies for mitigating the spread of COVID-19 and have created a new normal. COVID-19 is different from influenza and previous pandemic diseases, such as SARS, MERS, and EVD, but has some similarities to them. Influenza and these pandemic diseases are introduced in this paper as a comparison with COVID-19. The features of COVID-19, progress achieved in treatment, emerging technologies in testing and diagnosis, and current and future challenges are presented. Specifically, topics regarding COVID-19 in this paper cover basic facts, the questionable origin of COVID-19, testing and diagnosis, pharmaceutical treatment and comfort measures, strategies and management for fighting against COVID-19, and the emotional, psychological, and mental health impacts of shelter-in-place orders and quarantine of COVID-19.