Microsoft cofounder Bill Gates said the world was entering into "uncharted territory" because it was not prepared for a pandemic like COVID-19, the disease caused by the novel coronavirus.

Speaking to "BBC Breakfast" by video chat on Sunday, Gates said the world should've invested more in mitigating a global health crisis.

"There is the period where the virus shows up in those first few months," he said. "Were the tests prepared? Did countries think through getting their ICU and ventilator capacity up?"

He added that once the crisis is over "very few countries are going to get an A grade" for their handling of the outbreak.

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Microsoft cofounder Bill Gates said the world was entering into "uncharted territory" because it was not prepared for a pandemic like COVID-19, the disease caused by the novel coronavirus.

Gates, who has been warning about the risk of a pandemic disease for years and who has poured millions into fighting the new coronavirus outbreak, told "BBC Breakfast" on Sunday that the world should have invested more into mitigating a global health crisis.

"Well, there was a period when I and other health experts were saying that this was the greatest potential downfall the world faced," he told the BBC in an interview on Sunday, highlighting his previous warnings against the possibility of a deadly pandemic.

"So we definitely will look back and wish we had invested more," he said, "so that we could quickly have all the diagnostics, drugs, and vaccines. We underinvested," he said.

The 67-year-old billionaire warned that in the period before COVID-19 became a public-health crisis, countries could have better prepared their testing capabilities and made sure hospitals were stocked with ventilators and other necessary health supplies.

"There is the period where the virus shows up in those first few months," he said. "Were the tests prepared? Did countries think through getting their ICU and ventilator capacity up?"

He added that once the crisis is over "very few countries are going to get an A grade" for their handling of the outbreak.

"Now, here we are, we didn't simulate this, we didn't practice," he said. "So both in health policies and economic policies, we find ourselves in uncharted territory."

Gates has become an outspoken advocate for preparing for a global health crisis like COVID-19.

Speaking to the Financial Times earlier this month, Gates said that COVID-19 was the "biggest event that people will experience in their entire lives" and world leaders and global policymakers have "paid many trillions of dollars more than we might have had to if we'd been properly ready."

He told FT he was confident that lessons learned from this outbreak would encourage people to better prepare for next time but lamented that the cost this time around was too high.

"It shouldn't have required a many trillions of dollars loss to get there," he said. "The science is there. Countries will step forward."