The next time the world faces an outbreak of a fast-spreading and deadly new pathogen, governments must act swiftly and be ready to restrict travel or mandate masks even before anyone knows the extent of the threat, according to a pair of new reports delivered to the World Health Organization.

The studies are intended to address missteps over the past year that led to more than 3.25 million deaths, some $10 trillion in economic losses and more than 100 million people pushed into extreme poverty.

“Current institutions, public and private, failed to protect people from a devastating pandemic,” concluded one of the reports, released on Wednesday, which called the Covid-19 pandemic “the 21st century’s Chernobyl moment.”

“Without change,” it said, these institutions “will not prevent a future one.”

The reviews, released in advance of this month’s meeting of the W.H.O.’s governing assembly, were written by appointees who donated countless hours in the midst of their own countries’ pandemic fights to interview hundreds of experts, comb through thousands of documents, gather data and seek counsel from public and private institutions around the world.