The founder of Microsoft has warned of bioterrorist attacks and has urged world leaders to use "germ games" to prepare for them.
Bill Gates said governments must get ready for future pandemics and smallpox terror attacks by investing billions in research and development.
During a sit-down interview with the chair of the Health Select Committee, Jeremy Hunt, for the think tank Policy Exchange, Mr Gates suggested "germ games" could be used to practise how to respond to such events.
He also called for the formation of a new billion-dollar World Health Organisation (WHO) Pandemic Task Force. "It'll take probably about a billion a year for a pandemic Task Force at the WHO level, which is doing the surveillance and actually doing what I call 'germ games' where you practice," he said. "You say, OK, what if a bioterrorist brought smallpox to 10 airports? You know, how would the world respond to that? "There's naturally-caused epidemics and bioterrorism-caused epidemics that could even be way worse than what we experienced today and yet, the advances in medical science should give us tools that, you know, we could do dramatically better.
"So you'd think this would be a priority. The next year will be where those allocations have to get made, including this global pandemic Task Force."
He added that countries, such as the US and the UK, will have to spend "tens of billions" on research and development (R&D) to prepare for the next pandemic.
But he said, that while research may be expensive, it could lead to other innovations such as eradicating the flu and the common cold. "I'm hoping in five years, I can write a book called, 'We ARE ready for the next pandemic', but it'll take tens of billions in R&D - the US and the UK will be part of that," Mr Gates said.
"The nice thing is a lot of the R&D we need to do to be ready for the next pandemic are things like making vaccines cheap, having big factories, eradicating the flu, getting rid of the common cold, making vaccines just a little patch you put on your arm, [are] things that will be incredibly beneficial even in the years when we don't have pandemics."
The world's fourth-richest man also said he will continue to talk about pandemic preparedness, as part of his work as a philanthropist.
Mr Gates said: "So along with the climate message and the ongoing fight against diseases of the poor, pandemic preparedness is something I'll be talking about a lot.
"And I think it'll find fertile ground because, you know, we lost trillions of dollars and millions of lives and citizens expect their governments not to let that happen again."
Mr Gates appeared at the COP26 climate summit on Tuesday, where he took part in a session on accelerating clean technology and met the Prince of Wales.