The World Health Organization has said it had completed the groundwork in China to probe the origins of the new coronavirus -- as it warned there might never be a "silver bullet" for Covid-19.
WHO chief Tedros Adhanom Ghebreyesus urged governments and citizens to focus on known basic steps to suppress the pandemic, such as testing, contact tracing, maintaining physical distance and wearing a mask.
"We all hope to have a number of effective vaccines that can help prevent people from infection," Tedros told a virtual press conference. "However, there's no silver bullet at the moment -- and there might never be.
"The basics of public health" are most effective for now, Tedros added, saying that wearing a mask in particular was sending a "powerful message to those around you that we are all in this together".
Infections are surging in some countries around the world, but Tedros insisted that however bad the situation was, past examples such as South Korea showed it could be turned around.
"When leaders step up and work intensely with their populations, this disease can be brought under control," he said.
The novel coronavirus has killed more than 690,000 people and infected nearly 19 million since the outbreak emerged in Wuhan in China last December, according to a tally from official sources compiled by AFP.
The WHO began pressing China in early May to invite in its experts to help investigate the animal origins of Covid-19. The UN health agency sent an epidemiologist and an animal health specialist to Beijing on July 10 to lay the groundwork for a probe aimed at identifying how the virus entered the human species.
Their scoping mission is now complete, said Tedros.
Tedros said WHO and Chinese experts had agreed the terms of reference and a programme of work for a WHO-led international team of scientists and researchers from around the world.
Scientists believe the killer virus jumped from animals to humans, possibly from a market in the city of Wuhan selling exotic animals for meat.