Omicron cannot be regarded as a "big flu", a senior medical expert from Tianjin warns.

"Patients usually have mild symptoms, or even no symptoms at the beginning. However, with the progress of the disease, we find that 42 percent of the positive infected patients in Tianjin develop standard symptoms," said Zhang Ying, deputy director of the Tianjin Center for Disease Control and Prevention.

"It has some manifestations of pneumonia, whether light or heavy," Zhang said in a CCTV interview on Tuesday.

With pneumonia reaching as high as 42 percent, it can't be equated with the flu, she said.

"We all know that the influenza virus mainly affects the upper respiratory tract," she said. "While some people with chronic underlying diseases will get pneumonia as a complication — bacterial or viral pneumonia — the proportion is far less than 42 percent."

According to Zhang, Tianjin has achieved a comprehensive victory in the fight against the latest round of the COVID-19 outbreak driven by Omicron.

It's not simply a question of the number of positive infected people but "depends on the group in which the positive people were detected". New positives are being found in quarantine venues, rather than circulating in society at large, and "that is a good signal", Zhang said.

"Meanwhile new positive infections in the city have been placed under quarantine for more than two weeks. In other words, there is no risk of transmission in society, outside the quarantine venues," she said. "Therefore, this round of the COVID-19 outbreak in Tianjin is under control."

Zhang believes all locked-down communities and housing estates in Tianjin will return to normal before the end of January, allowing local residents to have a happy Lunar New Year holiday beginning in February.