In early February, 57 people arrived at a Nebraska military base, among the first Americans evacuated from Wuhan, China, the epicenter of the new coronavirus outbreak. U.S. health officials knew very little then about the mysterious new virus, and the quarantined group offered an early opportunity to size up the threat.

The federal government sought help from a team at the University of Nebraska Medical Center, including Dr. James Lawler, an experienced infectious disease specialist. Lawler said he immediately asked the world-renowned U.S. Centers for Disease Control and Prevention (CDC) for permission to test the quarantined group, deeming it crucial to know whether people without symptoms were infected and could spread the deadly pathogen.

Agency officials worried that detained people couldn’t give proper consent because they might feel coerced into testing. "CDC does not approve this study,” an official at the quarantine site wrote to Lawler in a Feb. 8 email obtained by Reuters. "Please discontinue all contact with the travelers for research purposes.”