China on Tuesday announced a second confirmed case of the omicron variant of COVID-19 after a 67-year-old man tested positive after more than two weeks of isolation, state media reported.
The man had tested negative for the virus as he quarantined for two weeks after returning from overseas on Nov. 27, state broadcaster CCTV reported.
The presence of the omicron variant wasn't detected until he went home for a further week of self-isolation in the southern city of Guangzhou.
The epidemic control and prevention center in the northern port city of Tianjin had earlier confirmed a first case of omicron in a Polish national who arrived in China from Warsaw, testing positive on Thursday.
The teenager is in isolation in the northern port city of Tianjin, the ministry said.
Chinese virologist Zhang Wenhong warned the ruling Chinese Communist Party (CCP) that the omicron variant is "a very urgent matter" requiring a change in the way the country develops vaccines against COVID-19.
"We must adjust all vaccination systems and shift to influenza vaccination mode by developing new vaccines promptly every year according to the virus variants," Zhang, who directs the National Center of Infectious Diseases, wrote in a commentary carried by Caixin news. "It means tougher challenges in the future."
But he added: "China is now in a strategically advantageous position brought by the dynamic zero-tolerance strategy, as it speeds up efforts to build scientific support for the regular epidemic control in the next stage, including developing vaccines and medicines reserves to support the rest of the world, as well as public health preparedness."
Gao Fu, director of the Chinese Center for Disease Control and Prevention, called on people to keep getting vaccinated, while COVID-19 expert Zhong Nanshan said at least 83 percent of China's 1.4 billion population will need three jabs, assuming that three jabs are around 70 percent effective at preventing infection.
"We need a third dose of an mRNA vaccine after two doses of inactivated virus vaccine," Zhong said. "But we will need to observe infection rates in the real world to confirm this."
Quality, safety concerns
Yang Jinxia, professor of biology at Manhattanville College in New York State, pointed to a relatively low death rate shown in data now emerging from South Africa.
"[Nonetheless], there are concerns about the quality and safety of vaccines in China," Yang said. "Data shows that there is a greater level of antibody protection if a third shot is given."
"China may manage to control the outbreak in the short term, but that's unlikely to be sustainable, because they can't stop people coming and going forever," he said. "It's unsustainable."
Authorities in the eastern province of Zhejiang have placed more than half a million people in lockdown, with more than 50,000 in centralized quarantine facilities, local media reported, with similar measures in the eastern province of Jiangxi.
Jiangxi resident Zhan Quanxi said many of China's homegrown vaccines are made with deactivated virus rather than mRNA.
"China mainly uses inactivated vaccines, which aren't totally useless, but the effectiveness is quite low, while its mRNA vaccines aren't as good as the [overseas] ones."
"A lot of vested interests are making huge amounts of money out of selling vaccines right now," he said.
Translated and edited by Luisetta Mudie.