SHANGHAI, Jan 20 (Reuters) - Strict COVID-19 testing requirements for the Beijing Winter Olympics could see more athletes from high-risk Omicron regions banned from participating, but the system in place will be as flexible as possible, an Olympic medical adviser told Reuters. Experts have warned that China"s strict "zero-COVID" strategy, as well as its more sensitive testing protocols, could see more athletes excluded from the Games scheduled to take place between Feb. 4 and Feb. 20 - especially from regions that have seen a spike in the highly infectious Omicron variant. "Some people might not make it, but we are trying to put in place ways in which they can prove with extra testing that although they did have Omicron, they are no longer infectious and can be allowed into China," said Brian McCloskey, a member of the International Olympic Committee"s Medical Expert Panel advising on health measures. "But it is the countries that saw the early spike in cases that will be the most engaged with it (the testing system)," he told Reuters. The Games will proceed in a "closed loop" that will keep overseas athletes from mingling with the Chinese population, and China has also as a precaution restricted spectator ticket allocations. While some countries are trying to manage the transition from "pandemic" to "endemic", China has focused on stamping out new transmission chains as soon as they arise. read more That involves a stringent quarantine policy, city-wide lockdowns and mass testing programmes that kick in as soon as any outbreaks occur, and hosting the Winter Olympics is a major test, said McCloskey. "They are taking a risk on their zero-COVID strategy that they wouldn"t have had to take if they didn"t have the Olympics," he said. Still, the handling of Swiss snowboarder Patrizia Kummer, who is not vaccinated, shows that China is showing some flexibility, with the athlete allowed to quarantine for three weeks instead, McCloskey added. The risks of hosting international sports events during the pandemic have come under fresh scrutiny this week after Australia deported the unvaccinated tennis star Novak Djokovic on Sunday for violating the country"s COVID-19 entry rules. read more McCloskey said that while COVID-19 was a particular challenge, public health risks have long been a major concern for Olympic organisers, with the Zika virus also testing organisers in Brazil in 2016. "My expectation is that we will not be dealing with COVID in the same way for 2024," he said. "But we will have to have surveillance systems in place to make sure that should anything happen either in the build up to the games or during them, that we will recognise it very quickly and respond very quickly."