In the three months since Johnson & Johnson’s COVID-19 vaccine received emergency use authorization from the U.S. Food and Drug Administration, more than 10 million Americans have received the vaccine, according to the Centers for Disease Control and Prevention. The single-shot viral vector vaccine—developed in collaboration with Beth Israel Deaconess Medical Center (BIDMC) immunologist Dan Barouch, MD, Ph.D.—was authorized for use based on clinical trial data showing strong clinical efficacy against symptomatic COVID-19 in the United States, Latin America and South Africa.