WHO emergencies director Michael Ryan said the organisation was "confident" in the COVID-19 countermeasures being put in place by Beijing 2022 and the International Olympic Committee (IOC), which includes all participants entering a "closed-loop management system".

The closed loop, under which all attendees travelling into the city will undergo daily testing for COVID-19 and be unable to access the outside world for the duration of their time in Beijing, came into effect earlier this week prior to the opening of the Games on February 4.

Concerns over the spread of COVID-19 have grown in recent weeks following the emergence of the Omicron variant, while at least two Chinese cities have entered new lockdowns due to rising coronavirus cases.

"The Chinese authorities have very strict measures in place, and they’ve released a series of different playbooks," Ryan said.

"We continue to review those playbooks with the IOC.

"I’m confident that, given the information we have, that the measures that are in place for the Games are very strict and very strong and we don’t, at this point, see any increased risk of disease transmission in that context."

Ryan added: "We will continue to monitor the situation.

"But certainly at this stage, given the arrangements that have been put in place for the athletes by the organisers, we don’t perceive that there’s any particular extra-risk in hosting or running the Games.

"But obviously we will keep all of the measures that are being put in place are under constant review."

The IOC has urged all participants at the Games to be extra vigilant before they travel to China.

The second version of the playbooks was released last month, with updates including that all of the Beijing 2022 workforce entering the closed-loop bubble system would receive a COVID-19 booster vaccination at least 14 days before starting their role, provided they are eligible.

Athletes, officials and journalists attending Beijing 2022, scheduled to conclude on February 20, are not required to have a booster to be admitted to the closed loop.

Unvaccinated participants must complete a three-week quarantine before they are allowed to travel to venues.

The measures set to be in operation at Beijing 2022 are stricter than for the Tokyo 2020 Olympics, postponed to last year because of the pandemic.

The IOC claimed last month that Tokyo 2020 did not result in increased COVID-19 cases in Japan.