In his foundation’s annual letter, published on Wednesday, founder of Microsoft, billionaire Bill Gates has called for a massive global effort to prepare for future pandemics the threat of which he says needs to be treated with the same degree of seriousness as the threat of war.

“Stopping the next pandemic will require spending tens of billions of dollars per year — a big investment, but remember that the COVID-19 pandemic is estimated to cost the world $28 trillion,” he added.

“The world needs to spend billions to save trillions (and prevent millions of deaths),” Gates said.

Gates urged rich countries to provide the bulk of the investment, pointing out that their governments stand to benefit most.

Investments in future diagnostic and vaccination technologies should be supplemented by “a global alert system, which we don’t have at large scale today,” allowing epidemics to be detected and responded to early, the letter said.