Speaking to the media Thursday from the sidelines of the UN General Assembly in New York, Tedros Adhanom Ghebreyesus appeared less upbeat about the end of the COVID-19 pandemic, making clear that "being able to see the end, doesn't mean we are at the end."
Last week, Tedros told reporters that the world had "never been in a better position to end the pandemic... The end is in sight."
And US President Joe Biden went further in an interview broadcast Sunday, declaring that the pandemic in the United States "is over."
Tedros stated again that the world was in the best position it had ever been in to end the pandemic, with the number of weekly deaths continuing to drop -- and now just 10 percent of what they were at the peak in January 2021.
The WHO chief pointed out that two-thirds of the world's population has been vaccinated, including three-quarters of health workers and older people.
"We have spent two-and-a-half years in a long, dark tunnel, and we are just beginning to glimpse the light at the end of that tunnel," he said.
But, he stressed, "it is still a long way off, and the tunnel is still dark, with many obstacles that could trip us up if we don't take care."
"We're still in the tunnel."
In its latest epidemiological update, the WHO said over 9,800 fatalities were reported last week, down 17 percent from a week earlier, while 3.2 million new cases were reported.
The UN health agency has warned that the falling number of reported cases is deceptive, since many countries have cut back on testing and may not be detecting less serious cases.
Maria Van Kerkhove, the WHO's technical lead on Covid, told reporters the virus is still "circulating at an intense level," although the situation varied in different countries.
But she pointed out that the world has the tools needed to rein in the spread.
"Our goal is to end the emergency in all countries. And we will keep at this until we reach that goal," she said.
Since the start of the pandemic, the WHO has tallied more than 609 million cases and some 6.5 million deaths, though the true toll is believed to be substantially higher.
A WHO study published in May based on excess mortality seen in various countries during the pandemic estimated that up to 17 million people may have died from Covid in 2020 and 2021.