Ali was the last person to be infected with naturally occurring smallpox anywhere in the world. After contracting the virus, he made a full recovery and then decided to devote his life to the cause of vaccinations and illness prevention. He did so until his sudden passing in his home district of Merka on 22 July 2013. At the time, he was working with WHO as a district polio officer as part of the polio eradication programme. He was 59 years old.