A volunteer is delivering necessities to a local resident in a community under lockdown in Xi'an, Shaanxi Province. Photo: VCG

Newly confirmed infections in Xi'an, home to the Terracotta Warriors in Northwest China's Shaanxi Province, are expected to see a downward trend after a week, experts said, after the city on Monday hit a record high one-day number of new COVID-19 confirmed cases.

The city registered 175 confirmed cases on Monday, the biggest one-day figure since the latest outbreak on December 9, and also marking the third consecutive day for Xi'an to report more than 150 domestically transmitted cases.

Xi'an, a mega-city with a population of over 13 million, upgraded its city lockdown measures on Monday at midnight, just four days after it imposed a quasi-lockdown on December 23. 

Zhang Yuexin, a medical expert specializing in epidemic prevention and control, told the Global Times on Tuesday that such a big number of confirmed cases is a result of frequent mass nucleic acid testing, indicating more patients are being found in risky zones that were previously unknown. 

The strict lockdown will effectively slow viral transmission among communities, and the number of newly confirmed cases in a single day is expected to experience a downward trend after one week, Zhang said. 

Zhang added that clinical experience showed that patients with the Delta variant demonstrated a shorter period of onset of illness, with most patients starting to shed the virus in three or four days, meaning more potential cases will be easily detected in the following days of mass nucleic acid testing.

The lockdown was dubbed as the most strict measure taken by a mega-city with a population over 10 million since the Wuhan lockdown in 2020. 

Almost two years ago on January 23, 2020, Wuhan locked down the entire city, and it took 76 days for the historic lockdown to end.

Zhang said that Xi'an would need less time to lift its lockdown than Wuhan. Unlike the lockdown in Wuhan, which was adopted in a situation when people had no clear understanding of the virus, the one in Xi'an is based on the fact that China has accumulated two years of experience in handling the cunning COVID-19. 

The lockdown will not be lifted all at once, but in a gradual and phased pace in accordance with the risk, Zhang noted. 

A team of 150 military medics from the Air Force Medical University started to take charge of quarantine zones of the COVID-19 designated hospitals in Xi'an after they were sent to assist city on Monday night. Many had experience in fighting the epidemic in Wuhan. 

As local residents are asked to stay indoors after the city government announced the previous outdoor purchasing policy became invalid on Monday, topics related to how difficult it is to purchase fresh vegetables trended on social media Sina Weibo on Tuesday. 

A resident surnamed Lu told the Global Times "it's quite desperate to experience a city lockdown. Other than to take a nucleic acid test, we are not allowed to step out of our home. My vegetables will last for two more days. "

Hopefully, the epidemic will end around Spring Festival, Lu said, expressing her confidence toward anti-epidemic efforts made by the city government. 

Xi'an started a fresh round of mass nucleic acid testing on Monday and tightened its policy of lockdown by requiring all residents to stay home to guarantee the accuracy of the test results.