It begins with a mild fever and malaise, followed by a painful cough and shortness of breath. The infection prospers in crowds, spreading to people in close reach. Containing an outbreak requires contact tracing, as well as isolation and treatment of the sick for weeks or months.

This insidious disease has touched every part of the globe. It is tuberculosis, the biggest infectious-disease killer worldwide, claiming 1.5 million lives each year.

In April, with hospitals overwhelmed and much of the United States in lockdown, the Department of Health and Human Services produced a presentation for the White House arguing that rapid development of a coronavirus vaccine was the best hope to control the pandemic.

“DEADLINE: Enable broad access to the public by October 2020,” the first slide read, with the date in bold.