With the end of a two-week quarantine, World Health Organization experts are preparing to start their investigation into the origin of the coronavirus in Wuhan, more than a year after the outbreak of the pandemic.

Thursday, about ten team members boarded a bus that took them to an undisclosed destination.

The investigation, which China took more than a year to organize, is very sensitive for the Communist regime, which seeks to avoid any responsibility for the outbreak of the pandemic.

While China was able to stop the infection on its soil, the virus spread throughout the world, leaving 2.1 million deaths.

Chinese government experts initially said the pandemic appeared in a market in Wuhan where live wild animals are sold. Hence, the virus is believed to have passed from bats to other animal species before being transmitted to humans.

The market has been closed for more than a year and is surrounded by a long blue fence.

But the Chinese media, supervised by the ruling Communist Party, gradually rejected this theory, instead adopting the theory that the virus was brought in from outside China, perhaps through frozen meat.

The World Health Organization has ruled out the hypothesis of transmission through food, but it seems that many Chinese today are convinced that the pandemic is of American origin.

Last year, a Chinese Foreign Ministry spokesman said without providing evidence that the virus may have been introduced to Wuhan at the end of 2019 by US soldiers who came to participate in a sports competition.

Outside of China, various hypotheses have also been circulated, including the theory that the virus was transmitted intentionally or unintentionally from the Wuhan Fever Laboratory where corona viruses were experimentally manufactured.

Both the lab and the Chinese government have vehemently denied this hypothesis, put forward specifically by former US President Donald Trump.

For now, the World Health Organization is keen not to speculate.

"All hypotheses are on the table. It is clear that it is too early to conclude on the origin of this virus, whether in China or outside China," said Michael Ryan, director in charge of emergency matters at the organization.

- Washington on the lookout -

The researchers' program is unknown and there is no guarantee they will be able to visit the diet lab or marketplace that was behind the first hypotheses.

Many experts fear that after a year there is not much left to be found to identify the origin of the virus.

While Donald Trump accused the World Health Organization of submitting to Beijing's orders, the new US administration called Wednesday for a "clear and in-depth" international investigation.

"It is necessary to go to the heart of things to uncover how the pandemic emerged in China," White House spokeswoman Jane Saki said. She added that Washington "will assess the credibility of the investigation report upon completion."

But this warning angered Beijing, whose Foreign Ministry spokesman Zhao Lijian told reporters that China hopes the United States can "respect facts and science, respect the hard work of the WHO expert team (...)" and allow them to work "away from any political interference." 

Aside from the scientific aspects, Beijing has been accused of delaying action in response to the first infections recorded in Wuhan in December 2019, or even earlier.

Last week, a commission authorized by the World Health Organization estimated that "Chinese local and national authorities could have imposed public health measures more forcefully in January 2020."

Families of Covid victims have accused Beijing of trying to prevent them from contacting WHO representatives and called on experts not to be deceived.

It is not known how long the investigation will take, but China will begin the long Lunar New Year holiday Feb. 11, wherein business in the country will be halted for almost a week.