The WHO and Beijing have spent months negotiating the terms of the mission, which has been delayed several times, and the United Nations agency's researchers say they don't have a clear understanding of the progress that Chinese scientists have made in what is meant to be a collaborative effort.
"We are looking for the answers here that may save us in future - not culprits and not people to blame", the WHO's top emergency expert Mike Ryan told reporters this week, adding that the organisation was willing to go "anywhere and everywhere" to find out how the virus emerged.
According to WHO's published agenda for the research team, there are no plans to assess whether there might have been an accidental release of the coronavirus at the lab, as some American politicians, including President Donald Trump, have claimed. But two members tested positive for IgM antibodies.
Two members have been forced to remain behind after they tested positive for coronavirus antibodies.
The 10-strong team is expected to arrive Thursday in Wuhan, the central Chinese city where the virus was first detected in late 2019.
Meanwhile, Shijiazhuang, North China's Hebei Province, the epicenter of the most recent COVID-19 outbreak, began building 3,000 makeshift housing units to be used as quarantine venues for COVID patients on Wednesday amid surging infections.
A government spokesman said this week the World Health Organization team will "exchange views" with Chinese scientists but gave no indication whether they would be allowed to gather evidence. In addition, 78 new asymptomatic cases were also reported which China does not classify as confirmed cases.
Last week, World Health Organization director-general Tedros Adhanom Gheybreyesus said he was "very disappointed" that China had still not authorised the team's entry for the long-awaited mission, but on Monday, he welcomed its announcement of their planned arrival. The market remained closed and sealed since early previous year.
Other team member Marion Koopmans, a virologist at Erasmus University Medical Center in the Netherlands, said last month it was too soon to say whether the SARS-CoV-2 virus had jumped directly from bats to humans or had an intermediate animal host.
It's been a year since the first reports of the disease emerged in Wuhan.
Workers stand next to Wuhan residents wearing face masks waiting in a line to be tested of COVID-19 in a neighborhood in Wuhan, in China's central Hubei province on 15 May 2020.
China's relatively low case figures are a testimony to the effectiveness of strict containment, tracing and quarantine measures, but have also raised questions about the tight hold the government maintains on all information related to the outbreak. Almost 2 million people have died due to the coronavirus, with more than 92 million infections, according to Johns Hopkins University.