Bill Gates has warned governments must prepare for future pandemics and smallpox terror attacks by investing billions of dollars in research and development.
Gates made the warning on Wednesday during a Policy Exchange interview with the chair of the UK Health Select Committee Jeremy Hunt.
The Microsoft founder also called for the formation of a new billion-dollar World Health Organisation Pandemic Task Force.
While the research may be expensive, he said that it could also lead to other innovations, such as eradicating flu and the common cold.
He said that countries like the US and the UK must spend "tens of billions" to fund the research.
"I'm hoping in five years, I can write a book called, 'We ARE ready for the next pandemic', but it will take tens of billions in R&D - the US and the UK will be part of that", he said.
"It will 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 practise."
Gates suggested the "germ games" could include preparing for acts of bioterrorism such as smallpox attacks on airports.
"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", he said.
"There's naturally-caused epidemics and bioterrorism-caused epidemics that could even be way worse than what we experienced today"
Despite the dire warning, the world's fourth richest man also struck an optimistic note during the interview, anticipating the "incredibly beneficial" medical innovations that will come from increased funding for pandemic prevention.
"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, things that will be incredibly beneficial even in the years when we don't have pandemics," he said.
He added that he will continue to talk about pandemic preparedness, as part of his work as a philanthropist.
He 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 will 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."