In 2014, in the face of an unprecedented Ebola epidemic in western Africa, Piot and other scientists called for the emergency release of the experimental ZMapp vaccine for use on humans before it had undergone clinical testing on humans. That year, he was appointed by Director General Margaret Chan to the World Health Organization's Advisory Group on the Ebola Virus Disease Response, co-chaired by Sam Zaramba and David L. Heymann. He also chaired an independent panel convened by Harvard Global Health Institute and the London School of Hygiene & Tropical Medicine into the national and international response to the epidemic, which sharply criticised the response of the WHO and put forward ten recommendations for the body's reorganisation. In February 2020, he criticised the delay in declaring the 2019–20 novel coronavirus outbreak focused on Hubei, China, a Public Health Emergency of International Concern, and advocated a five-point scale for outbreaks, rather the current binary (emergency/no emergency) system.