People line up outside a makeshift nucleic acid testing site during a mass testing for the coronavirus disease (COVID-19) in Haidian district of Beijing, China April 26, 2022. REUTERS/Carlos Garcia Rawlins

"As many countries reduce testing, WHO is receiving less and less information about transmission and sequencing," Director-General Tedros Adhanom Ghebreyesus told a news conference at the U.N. agency's headquarters in Geneva.

"This makes us increasingly blind to patterns of transmission and evolution."

Bill Rodriguez, chief executive of FIND, a global aid group working with WHO on expanding access to testing, said "testing rates have plummeted by 70 to 90%."

"We have an unprecedented ability to know what is happening. And yet today, because testing has been the first casualty of a global decision to let down our guard, we are becoming blind to what is happening with this virus," he said.