GENEVA, Switzerland — The number of newly reported COVID-19 cases has dropped dramatically, the World Health Organization said Wednesday, urging the world to seize the opportunity to end the pandemic.

But the WHO said that future coronavirus waves are expected and that governments across the world need to remain vigilant and ready to respond to any threat that may emerge.

Newly reported cases of the disease, which has killed millions since being identified in late 2019, last week fell to the lowest level since March 2020, said WHO chief Tedros Adhanom Ghebreyesus.

"We have never been in a better position to end the pandemic," he told reporters. "We are not there yet, but the end is in sight."

But the world needed to step up to "seize this opportunity," he added.

"If we don't take this opportunity now, we run the risk of more variants, more deaths, more disruption, and more uncertainty."

'Underestimate'

According to the WHO, during the week of Sept. 5-11, the number of new weekly cases worldwide decreased by 28 percent over the previous week to over 3.1 million. The number of new weekly deaths was down 22 percent to just under 11,000.

Tedros likened the pandemic response to a marathon race. "Now is the time to run harder and make sure we cross the line and reap the rewards of all our hard work."

Nevertheless, the WHO's experts continue to urge caution.

The virus is "circulating at a very intense level around the world at the present time. And, in fact, the number of cases that are being reported to the WHO we know are an underestimate," Maria Van Kerkhove, technical lead of the WHO's Health Emergencies Program, said.

"We feel there are far more cases that are actually circulating than are being reported to us," she said.

"We expect there to be future waves of infection, potentially at different time points throughout the world, caused by different subvariants of Omicron or even different variants of concern," she noted.

Those future waves of infection "do not need to translate into future waves of death, because we have tools that can prevent infections," she said.

Even as the pandemic wanes, people should maintain high levels of vigilance, said Mike Ryan, executive director of the WHO's Health Emergencies Program.

The world is fighting "a highly mutable evolving virus that has shown us, time and time again in two and a half years, how it can adapt and how it can change," said Ryan.

Since the start of the pandemic, WHO has tallied more than 600 million cases, and some 6.4 million deaths, although both those numbers are also believed to be serious undercounts.

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-19 in 2020 and 2021.

'Seize this opportunity'

In a bid to help countries to do what is needed to rein in the virus, the WHO on Wednesday published six policy briefs.

Among the recommendations, the WHO is urging countries to invest in vaccinating 100 percent of the most at-risk groups, including health workers and the elderly, and to keep up testing and sequencing for the virus.

"These policy briefs are an urgent call for governments to take a hard look at their policies, and strengthen them for COVID-19 and future pathogens with pandemic potential," Tedros said.

"We can end this pandemic together but only if all countries, manufacturers, communities and individuals step up and seize this opportunity."

WHO emergencies director Michael Ryan agreed.

"Even as the pandemic wanes, and as the number of cases may drop, we are going to have to maintain high levels of vigilance," he told reporters.

"We still have a highly mutable, evolving virus that has shown us time and time again over two and a half years how it can adapt, how it can change."