The rapid spread comes despite about 75% of China's population -- or more than a billion people -- being fully vaccinated, according to Mi.
The caseload of China's latest outbreak pales in comparison with those of some other countries, including Singapore and the United Kingdom. But the scope of its spread has worried the Chinese government, which insists on a strict zero-Covid policy to stamp out infections. The outbreak was first detected on October 16 among a tour group of fully vaccinated senior citizens from Shanghai who traveled in several northern regions. Among the 133 infections reported as of Sunday, 106 were linked to 13 tour groups, according to Mi, the NHC health official.