People across the world, particularly those in developing countries, face a decade at risk from pandemics spread by antibiotic-resistant bugs, the billionaire Bill Gates has warned.

Gates, who made his fortune with the Microsoft Windows operating system before becoming a philanthropist, said the success of antibiotics had created complacency that was now being exposed by the rise of microbial resistance to the drugs.

“I cross my fingers all the time that some epidemic like a big flu doesn’t come along in the next 10 years,” Gates told a special edition of Radio 4’s Today programme guest-edited by Dame Sally Davies, the chief medical officer for England.

“I do think we will have much better medical tools, much better response, but we are a bit vulnerable right now if something spread very quickly like a flu that was quite fatal – that would be a tragedy and new approaches should allow us to reduce that risk a lot.”

Gates said it was crucial for wealthier countries to step in to help the developing world fight disease, both for humanitarian reasons and for their own health security.

Although mistakes were made, criticism of the World Health Organisation (WHO) during the Ebola crisis in west Africa was unfair, he said, because it was not funded or staffed to do all the things that observers wanted it to do.

International cooperation had led to the eradication of smallpox, and was on the verge of eradicating polio, he added.

“The cooperation that we have seen, I think, needs to intensify,” Gates said. “It’s the only way that global problems like epidemics will get solved and so [for] all the people who are negative on WHO, the message to take away from that is not that that kind of multilateral cooperative effort is doomed and the money is not well spent, rather that we actually need to broaden their capacity. We actually need to dedicate ourselves to this global cooperation.”

In September the UN secretary general, Ban Ki-moon, warned that antimicrobial resistance was a “fundamental threat” to global health that risked making high quality universal healthcare impossible.

It is estimated that more than 700,000 people die each year from drug-resistant infections, though it could be much higher because there is no global system to monitor the figures. There has also been difficulties in tracking death tolls even in places where they are monitored, such as the US, where tens of thousands of deaths have not been attributed to superbugs, according to a Reuters investigation.

The European Centre for Disease Prevention and Control reported in November that illnesses resistant to so-called last-line antibiotics – drugs kept in reserve for use against pathogens that have proved resistant to all other antibiotics – were on the rise in the continent.

Without them, some infectious diseases could become untreatable and some forms of major surgery would again become perilous.

Davies said Britain’s health service was well placed to handle a flu pandemic, although it would still take as long as six months to “produce enough vaccine to start putting it into people”. She was less optimistic about how resilient the rest of British society would be to an outbreak.

“It’s not just the NHS,” she said. “It’s how would our social care system cope with people who aren’t ill enough to be in hospital but need extra support? It’s how would our economy cope if a large proportion are too ill to work? When we have a just-in-time ordering policy for delivery of food, petrol, whatever.

“And if you think about the issues that could happen here if we had a recurrence of the 1918 type flu, then what would it be like in middle- and low-income countries where they don’t have the health systems to look after the patients?”