The ambitious campaign in Congo to curb the Ebola outbreak is the first widespread use of a vaccine since the devastating 2014 epidemic in West Africa.
The United States is also sending personnel from the CDC and equipment from the USAID.
Timothy Ziemer's departure Tuesday and the disbanding of his team at the National Security Council signal a downgrading of global health security as a priority, experts warn.
Many victims, ranging in age from 1 to 88, have been hospitalized in the outbreak of E. coli illness, the worst in a dozen years.
Robert Redfield's initial salary sparked controversy because it was almost twice that of his predecessor's.
The growing number and spread of these diseases pose an increasing risk in the United States.
Robert Redfield is earning almost twice what his predecessor made and more than past directors, as well as more than his current boss.
At least 46 people have been hospitalized in the multistate outbreak, the largest involving the bacteria in a dozen years.
The billionaire philanthropist says the United States and the rest of the world lack a sense of urgency to counter biological threats.
The disease is common among older adults, and usually treatable with antibiotics.