In China, authorities have expanded the number of cities on lockdown to 10, affecting some 33 million people, as medical workers struggle to slow the spread of a novel strain of coronavirus. At least 26 people have died of complications from the virus, which causes flu-like symptoms and is most dangerous to young children and the elderly. Most of China’s movie theaters — some 70,000 theaters in all — have been closed temporarily. A small number of coronavirus cases have been reported in Japan, Singapore, South Korea, Taiwan, Thailand, the United States and Vietnam.