Researchers have found evidence that a coronavirus epidemic swept East Asia some 20,000 years ago and was devastating enough to leave an evolutionary imprint on the DNA of people alive today. The new study suggests that an ancient coronavirus plagued the region for many years, researchers say. The finding could have dire implications for the Covid-19 pandemic if it’s not brought under control soon through vaccination. Four other coronaviruses can also infect people, but they usually cause only mild colds. Scientists did not directly observe these coronaviruses becoming human pathogens, so they have relied on indirect clues to estimate when...