CORONAVIRUS | The US set a record for coronavirus cases on Saturday, with more than 5 million people now infected, according to a Reuters tally, as the country’s top infectious diseases official offered hope earlier this week that an effective vaccine might be available by year-end.

With one out of every 66 residents infected, the US leads the world in Covid-19 cases, according to a Reuters analysis. The country has recorded more than 160,000 deaths, nearly a quarter of the world’s total...