After largely controlling the Covid-19 pandemic for 20 months, China’s “zero case” strategy faces its biggest challenge to date: the highly transmissible and virulent delta variant. As of Thursday (5), China had 533 new cases in 18 of the 31 provinces and cities at the provincial level, all caused by the delta mutation of the coronavirus. The rapid spread makes control measures more costly and sparks debate over whether the Chinese government should recalibrate its strategy.
The delta variant is ten times harder to control than the original virus, posing a huge challenge to China’s zero-case strategy, said Zeng Guang, chief epidemiologist at the China Centers for Disease Control and Prevention ( CDC) at a recent meeting. The approach relies on mass testing, aggressive contact tracing and community lockdowns.
Although the number of cases in China is still relatively low compared to the United States and other countries, the ability of the delta variant to infect people who have already been vaccinated and to spread much faster makes it more difficult to contain it. China needs to change its perspective on controlling the pandemic, Zeng said. This includes a shift in focus: no longer completely eliminating viruses and infections – which today seems impossible – and adopting common control measures, he said.
So far, China maintains its goal of zero cases and is pouring resources into testing, monitoring and quarantines. At a press conference Thursday with the Joint Control and Prevention Mechanism of the State Council, He Qinghua, an official with the National Health Commission, said the country will continue to pursue the strategy of “avoid imported cases and national resurgence”. The measures are clear, concrete and have proven to be effective, he said, and the outbreak could be largely controlled within weeks, provided local authorities strictly enforce the control measures.
mass tests
Meanwhile, the rapid transmission of the delta variant means an increased need for rapid testing, which increases the cost of disease control. This strain of coronavirus can reproduce in two to three days, which means that not only close contact with infected people, but also secondary contacts, must be traced, said Cai Weiping, an infectious disease specialist at the hospital. of the No. 8 People of Guangzhou.
Close contacts can be traced using “big data”, but the reach of secondary contacts can be enormous. “If we miss the early follow-up window, all we can do is mass test the whole city,” Cai said.
This is exactly what several cities in Guangzhou province, with more than 20 million inhabitants in total, have done in the past two months, after more than 100 cases have emerged. During this cycle of the epidemic, cities such as Nanjing, Zhangjiajie, Zhengzhou, Wuhan and Yangzhou have carried out extensive testing.
Under a guideline issued by the Joint Prevention and Control Mechanism, cities with less than 5 million inhabitants must complete nucleic acid tests in two days, while cities with more than 5 million must complete the nucleic acid tests in two days. complete in three to five days.
Massive nucleic acid testing is expensive. Currently, the kit ranges from 5.38 to 12.16 yuan per person (BRL 4.36 to BRL 9.87), and the testing service costs around 80 yuan per person (BRL 64.80). That’s at least 1.3 billion yuan ($ 1 billion) to test Guangzhou’s 15 million people.
To ensure greater accuracy, many cities perform more than one set of tests. The eastern city of Nanjing, for example, with 9.3 million people and where the latest outbreak started with more than 200 cases, carried out four rounds of tests in parts of the city in two weeks.
Some experts say mass testing is needed to avoid prolonged lockdowns, which could magnify the economic losses. “Measuring costs in the strict sense, mass testing certainly requires large amounts of labor and money, but it is necessary judging by the big picture,” said Zhao Dahai, executive director of the Joint Center. of Health Policy at Jiaotong-Yale University. Shanghai.
To protect people’s health and lives as much as possible, policymakers should test as widely as possible to eliminate any risks that could fuel the pandemic, said Wang Chenguang, professor of law at Tsinghua University.
Is reinforcement necessary?
Vaccines were once seen as a promising weapon to end the pandemic, but now it appears that the delta variant can infect people who have already been vaccinated, and they can infect others. When the local outbreak erupted at Nanjing Lukou International Airport, where nine workers tested positive for Covid-19 in July, more than 90% of airport workers had been vaccinated. In Ruili, a town in southwest Yunnan province on the border with Myanmar, where five cases were found in the last outbreak, nearly 97% of the population has been fully vaccinated.
China began vaccination against Covid-19 in December. More than 1.7 billion doses had been administered nationwide as of Aug. 3, according to the National Health Commission, according to a study released last month in Jiangsu Province. CDC, Fudan University, and Chinese vaccine maker Sinovac Life Sciences.
Global data shows that antibody levels in people who received Pfizer-BioNTech and other vaccines have also declined over time, prompting some countries to apply booster doses. Shao Yiming, a researcher at the Chinese CDC, said the country is considering using boosters to boost immunity against Covid, and that it has an “extremely low risk” of developing a large-scale epidemic.
Fudan’s study showed that a third dose of the vaccine produced by Sinovac resulted in a significant increase in antibody levels, but it was not clear whether the booster would be effective against the strains. Several countries, including Israel, Russia, the United Arab Emirates and Bahrain, have started offering boosters after outbreaks of infection. But many others, including the United States, have avoided making a decision on additional vaccines given the lack of scientific consensus on their need to maintain immunity.
The World Health Organization (WHO) has called on rich countries to stop distributing booster doses, citing vaccine inequalities across the world.
Coexistence with the virus
Whether a country abandons the zero-case strategy and opens its borders in the midst of the pandemic depends not only on its vaccination level, but also on its medical capacity, said Lu Mengji, a virologist at the University of Duisburg-Essen in Germany. “Tackling a pandemic pushes the epidemic curve to a level that medical capacity can support,” Lu said.
When the epidemic erupted in Wuhan, which already had a relatively high level of medical resources, the city came under medical “pressure” and received support from across the country. In the latest wave of the delta variant, cities like Zghangjiajie and Yangzhou, with scarce medical resources, have to rely on help from other provinces to treat the largest number of patients.
China’s medical capacity and the difference in medical resources across the country under pandemic pressure need to be measured more accurately, Lu said. Some medical resources should be reserved for non-Covid-related treatments, such as patients on dialysis and stroke.
The lack of intensive care units (ICUs) is a major concern. Intensive care beds in general hospitals in China account for around 3% of total beds, well below 15% in the United States. China has only 3.6 intensive care beds per 100,000 inhabitants. In the United States, the number was 34.2 in 2015, according to a work published by the National Biotechnology Information Center.
Germany had 29.2, according to a study published in the journal Intensive Care Medicine based on 2012 data. The intensive care beds in most Chinese hospitals are usually busy or even overcrowded, making it difficult to answer. to a public health emergency. During the Wuhan epidemic, more than 10% of the country’s intensive care medical staff were dispatched to support the city’s fight against the pandemic, highlighting the scarcity of public health reserve resources, according to a Chinese expert in intensive care.
The biggest challenge China faces is the uneven distribution of medical resources. Big cities with greater capacity may treat Covid-19 patients better, but in areas with poor medical resources, treatment capacity may not be sufficient, Lu said. experience in building makeshift hospitals. Equipped with oxygen ventilators and trained professionals in primary care wards, these temporary hospitals can greatly mitigate the impact of new cases on the medical system, Lu said.
There is a growing opinion that Covid-19 is likely to persist. Most virologists around the world agree that it has become a resident virus and the world will have to learn to live with it. Therefore, long-term planning for the rational allocation of medical and health resources is necessary, said Liu Guoen, director of the Center for Health Economic Research at Peking University. The unprecedented complexity of the pandemic is a warning that people must have more respect for the forces of nature and must begin to explore optimizing long-term prevention and control in a more scientific, rational, and way. systematic, Liu said.
“China has already given a satisfactory response in the first rounds of the pandemic,” said Zhang Wenhong, director of the National Center for Infectious Diseases and director of the infectious diseases department of Huashan Hospital, affiliated with the University. by Fudan. Choosing China will be an approach that secures a common future for humanity, helps achieve human connectivity and promotes a return to normal life while protecting citizens from the virus, Zhang said.
Ma Danmeng, Wang Lijun, Zhao Jinzhao, Xu Wen, Liu Denghui, Cao Yuan, Zhang Jinning and Denise Jia