Alex Azar’s face reddened when he heard the news: The only federally authorized tests to detect whether Americans were infected with the new coronavirus were flawed, and officials couldn’t identify what was causing the problem.

The Health and Human Services secretary listened on a speaker phone with advisers on Feb. 18, according to an attendee, as a senior Centers for Disease Control and Prevention official told him the agency hadn’t yet found a fix to the problem in the CDC-designed test.

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