On Sept. 23, 2020, a fourth Phase 3 clinical trial evaluating an investigational vaccine for coronavirus disease 2019 (COVID-19) has begun enrolling adult volunteers. The trial was designed to evaluate if the investigational Janssen COVID-19 vaccine (JNJ-78436725) can prevent symptomatic COVID-19 after a single dose regimen. Up to 60,000 volunteers will be enrolled in the trial at up to nearly 215 clinical research sites in the U.S. and internationally.