Gamblers and vacationers who had planned to visit U.S. casinos expressed a mixture of disappointment and relief over a wave of closings in at least 15 states as officials worked on slowing the spread of the coronavirus pandemic. Some said they still plan to visit casinos. Many casinos, where hundreds or even thousands of people touch the same slot machines and gambling chips, remain open. The casinos that remain open say they are stepping up cleaning and sanitization efforts.