Nurse Kathe Olmstead (right) gives volunteer Melissa Harting an injection in a study of a possible COVID-19 vaccine developed by the National Institutes of Health and Moderna Inc.

Nurse Kathe Olmstead, right, gives volunteer Melissa Harting, of Harpersville, N.Y., an injection as the world’s biggest study of a possible COVID-19 vaccine, developed by the National Institutes of Health and Moderna Inc., gets underway Monday, July 27, 2020, in Binghamton, N.Y. (AP Photo/Hans Pennink)