The History of Coronaviruses and Humanity

Several months into the COVID-19 pandemic, what we don’t know about COVID-19 still outweighs what we do know about the disease. Chinese researchers identified the causative virus as a novel coronavirus early in January 2020, making it the seventh known coronavirus to infect humans. Some coronaviruses circulate widely in humans, causing mild cold symptoms. Other coronaviruses have proven serious and deadly. How does the novel coronavirus fit into this picture?