LONDON — More than 20 heads of government and global agencies have called for an international treaty for pandemic preparedness that they say will protect future generations.

In a commentary published on Tuesday, WHO chief Tedros Adhanom Ghebreyesus and leaders including British Prime Minister Boris Johnson, Italian Prime Minister Mario Draghi and President Paul Kagame of Rwanda called for “a renewed collective commitment” to reinforce the world’s pandemic preparedness and response systems, that would be rooted in WHO's constitution.

“We are convinced that it is our responsibility, as leaders of nations and international institutions, to ensure that the world learns the lessons of the COVID-19 pandemic,” they wrote. Although they called for “solidarity” and greater “societal commitment,” there was no indication any country would soon change its own approach to responding to the pandemic.

But there are few details to explain how such an agreement might actually compel countries to act more cooperatively.

Last week, Tedros pleaded with rich countries to immediately donate 10 million COVID-19 vaccine doses so immunization campaigns could start in all countries within the first 100 days of the year. Not a single country has yet publicly offered to share its vaccines. Of the more than 459 million vaccine doses administered globally, most have been in just 10 countries — and 28% in just one.