“I need to be honest with you about something important. Most previous Ebola outbreaks in the Democratic Republic of Congo (DRC) were caused by a virus called Ebola Zaire, for which we have vaccines and treatments. This outbreak is caused by a different virus called Ebola Bundibugyo. There are currently no approved vaccines or treatments for it.” This was the stark message from Tedros Adhanom Ghebreyesus, director general of the World Health Organization (WHO) in an open letter to the people of the DRC, as he traveled to the country on Friday, May 29.

It is not surprising that a large Ebola outbreak would be considered a public health emergency of international concern. But the current PHEIC is notable for the speed with which it was declared, speaking to the urgency of the situation. World Health Organization Director-General Tedros Adhanom Ghebreyesus declared the outbreak a PHEIC on Sunday, May 17, without first convening an emergency committee. That step is unprecedented.