As China strives to contain its biggest COVID-19 surge in two years, officials and experts have urged continuation of the dynamic zero-COVID strategy and enforcement of science-based control measures to halt the spread of the virus.

Despite the large spike in new cases and challenges in blocking the highly transmissible Omicron variant, they said the goal of zero infection in communities must be achieved to protect medical systems from being overstretched and a jump in related deaths.

More sustainable response strategies should be devised, such as providing home test kits, antiviral pills and better preparing healthcare services.

The Chinese mainland reported 1,337 locally transmitted, confirmed infections for Sunday, down from over 1,800 the previous day. However, it was the second day in a row that confirmed infections topped 1,000.

The number of asymptomatic cases also went down by about 500 to 788 on March 13, according to the National Health Commission.

Lei Zhenglong, deputy head of the commission's Bureau of Disease Prevention and Control, said on March 14 that the recent epidemic has affected 27 provincial-level regions. As of March 13, more than 10,000 domestic infections had been reported this month.

The country's virus control strategy is still effective against the Omicron variant, but Omicron's stealth and rapid transmission means that faster and stricter measures should be taken, he said.

The hardest-hit regions include Jilin and Guangdong provinces and Shanghai.

Vice-Premier Sun Chunlan arrived in Jilin on March 13 to guide local virus control work, and visited a local high school and a residential complex.

The province registered 895 locally transmitted, confirmed cases, or nearly 67 percent of total cases nationwide for March 13, presenting a "severe and complicated situation", according to Sun.

During the inspection, she stressed local authorities should cope with the outbreak in a resolute, scientific, and effective manner, and strictly implement mass testing, quarantine and treatment protocols to achieve zero cases as soon as possible.

China approved on March 13 the use of rapid antigen testing kits, and Sun said screening for infections should be accelerated via both nucleic acid and antigen tests and improved organization.

More aid will be sent to Jilin to boost its ability to conduct epidemiological investigations. While high-risk groups must undergo centralized quarantine, people at lower risk can isolate at home, she said.

The latest outbreaks sweeping the Chinese mainland and the Hong Kong Special Administrative Region are mainly caused by the highly transmissible subvariant of Omicron, known as BA. 2, according to experts.

Zhang Wenhong, head of the infectious disease department at Fudan University's Huashan Hospital in Shanghai, said it is vital to stay confident, calm and clear-minded, and to not give up the fight against the virus.

"The infections in the mainland are still in the early stage of an exponential rise," he said on the microblogging platform Sina Weibo. "Because of a surge of cases in a relatively short span, many regions have appeared to be flustered."

With local authorities implementing targeted lockdowns and speeding up screening of key areas, Zhang said the virus' spread will eventually be slowed.

Based on discussions with virologists at the University of Hong Kong, he said the virulence of the new strain has decreased, and that fully vaccinated people and those with normal immune systems are unlikely to develop serious symptoms.

Only 0.1 percent of the 2,266 patients being treated in Shanghai over the past six months have been classified as having severe cases, and no one has died, he added.

Based on Hong Kong data, the death rate of people who aren't fully immunized is 23 times higher than those have received two shots.

Though the virus has become milder and less lethal, Zhang argues against relaxing virus containment policies.

"If China opens up too quickly, many people will get infected quickly, leading to a staggering number of hospitalizations, strained medical systems and an impact on society," he said. The consequences would be unimaginable for the elderly and those with underlying health problems who have not been vaccinated for fear of side effects, he said.

While it is vital for China to continue its strategy of achieving zero infection and bring the wave of Omicron infections under control, "it doesn't mean that we will impose lockdowns and mass testing persistently", he said.

When the outbreaks are stamped out, it is essential to seize the window of opportunity to develop smarter and more sustainable strategies, such as launching an extensive booster vaccine plan for seniors, ensuring the supply of oral antiviral medicine and affordable home testing kits, and developing fully trained triage medical services and home quarantine protocols, he said.