A bioterrorist attack capable of wiping out 30 million people is increasingly likely because it is easier to to create and spread deadly pathogens, Microsoft billionaire and philanthropist Bill Gates warns.
Speaking ahead of a speech at the Royal United Services Institute in London on Wednesday, Gates told The Telegraph an outbreak of smallpox, for example, would be more dangerous than even a nuclear attack.
"Bioterrorism is a much larger risk than a pandemic," he told the news outlet. "All these advances in biology have made it far easier for a terrorist to recreate smallpox, which is a highly fatal pathogen, where there is essentially no immunity remaining at this point.
"When you are thinking about things that could cause in excess of 10 million deaths, even something tragic like a nuclear weapons incident wouldn't get to that level. So, the greatest risk is from a natural epidemic or an intentionally caused infection bioterrorism events.
"Whether the next epidemic is unleashed by a quirk of nature or the hand of terrorist, scientists say a fast-moving airborne pathogen could kill more than 30 million people in less than a year. So, the world does need to think about this."
Gates said the ease and scope of modern travel enables a future pandemic that could be even more deadly than the Spanish Flu outbreak in 1919 that killed up to 100 million people.
"We will have epidemics in the next 20 years far worse than the Ebola epidemic, or the Zika epidemic, and there is some chance it would be a form of flu," he told the Telegraph.
"Something that is human-to-human respiratory that is like a measles, or a flu, or smallpox, that you need just one person on the bus, or plane, or the airport, and you get huge things. A health crisis somewhere is a health crisis everywhere."
"So, the scariest thing is something like the 1919 flu which really spreads everywhere and, because people are moving around more, it's easier for it to spread than back in 1919. If 1919 came back, we have no immunity to that strain."