On Saturday, February 18, 2017, Bill Gates spoke at the Munich Security Conference in Germany where he said, 
"It's time to redirect some of the money the world spends on weapons to prepare for a looming threat: terrorists with pathogens. He's warning that the threat of bio-terrorism is "right up there with nuclear war and climate change." 
He says it's now necessary for the world to prepare for what he considers to be one of its largest existential threats: the next pandemic. 
"Whether it occurs by a quirk of nature or at the hand of a terrorist, epidemiologists say a fast-moving airborne pathogen could kill more than 30 million people in less than a year. And they say there is a reasonable probability the world will experience such an outbreak in the next 10 to 15 years" he said.
The most recent pandemic was even more deadly than that, Gates pointed out. A flu outbreak that occurred naturally killed between 50 million and 100 million people in 1918.