U.S. health officials sparked criticism and confusion after posting guidelines on coronavirus testing from the White House task force that run counter to what scientists say is necessary to control the pandemic. The new guidance says it’s not necessary for people who have been in close contact with infected people, but don’t feel sick, to get tested. It was posted earlier this week on the website of the CDC. The CDC previously had advised local health departments to test people who have been within 6 feet of an infected person for more than 15 minutes. Across the country, public health experts called the change bizarre. They noted that testing contacts of infected people is a core element of public health efforts to keep outbreaks in check, and that a large percentage of infected people — the CDC has said as many as 40% — exhibit no symptoms.