A young volunteer helps to direct traffic at a junction where a screen is showing an ad for the 2022 Winter Olympics in Beijing on Thursday, Feb. 10, 2022. The possibility of a large outbreak in the bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Ng Han Guan)

Promoters at an event organized by sponsors of the 2022 Winter Olympics wait for visitors at a mall in Beijing on Thursday, Feb. 10, 2022. The possibility of a large outbreak in the bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Ng Han Guan)

Promoters at an event organized by sponsors of the 2022 Winter Olympics wait for visitors at a mall in Beijing on Thursday, Feb. 10, 2022. The possibility of a large outbreak in the bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Ng Han Guan)

Residents bring their children play on an art installation on display at a mall next to a venue which host the men's and women's ice hockey games at the 2022 Winter Olympics in Beijing, Thursday, Feb. 10, 2022. (AP Photo/Andy Wong)

Residents bring their children play ice skating at a mall next to a venue which host the men's and women's ice hockey games at the 2022 Winter Olympics in Beijing, Thursday, Feb. 10, 2022. The possibility of a large outbreak in the Olympic bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Andy Wong)

Residents visit a promotional event organized by sponsors of the 2022 Winter Olympics near a display of mascots of the Games at a mall in Beijing on Thursday, Feb. 10, 2022. The possibility of a large outbreak in the bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Ng Han Guan)

FILE - Two workers scan a tube after collecting swab samples from tables and chairs for COVID-19 testing at the main media center of the 2022 Winter Olympics, Feb. 10, 2022, in Beijing. The possibility of a large outbreak in the bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Jae C. Hong, File)

Residents walk by a barricaded venue which host the men's and women's ice hockey games at the 2022 Winter Olympics in Beijing, Thursday, Feb. 10, 2022. The possibility of a large outbreak in the Olympic bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Andy Wong)

Residents bring their children visit to a mall next to a venue which host the men's and women's ice hockey games at the 2022 Winter Olympics in Beijing, Thursday, Feb. 10, 2022. The possibility of a large outbreak in the bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Andy Wong)

Residents bring their children play near a barricaded venue which host the men's and women's ice hockey games at the 2022 Winter Olympics in Beijing, Thursday, Feb. 10, 2022. The possibility of a large outbreak in the bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Andy Wong)

FILE - A worker holds a COVID-19 test at the 2022 Winter Olympics, Thursday, Feb. 10, 2022, in Beijing. The possibility of a large outbreak in the bubble, potentially sidelining athletes from competitions, has been a greater fear than any leakage into the rest of China. (AP Photo/Natacha Pisarenko, File)