A health inspector checks the temperature of a passenger at a subway station in Guangzhou, a city on the forefront of China’s defense against new strains of Covid. Photo: Xinhua

China is calling for tighter seals on its borders as Covid-19 infections rise in its two southern megacities, where holes in their defenses have allowed the highly contagious delta strain to spread since May.

The lives of up to 60 million people in Guangzhou and Shenzhen, as well as surrounding areas, have been upended by the B.1.617.2 strain, also known as delta, which originated in India and the World Health Organization (WHO) warns could soon become the world’s dominant strain. The WHO recently described delta as the “fittest” of the viral strains.

Guangzhou has logged at least 153 cases of the variant in the month since the first patient surfaced. The woman had not traveled beyond the city limits for 12 months and thus the source of her infection puzzled epidemiologists.   

Other than quarantine for close contacts in locked-down communities, persistent citywide mass testing and restrictions on gatherings are in place for Guangzhou residents, who must produce a clean medical slate 48 hours before they venture outside the city.

Even so, there have been reports of travelers from Guangzhou being rounded up and isolated elsewhere in the nation. 

The city’s modest caseload by international standards does not appear to justify such draconian measures but Guangzhou is now being referred to as China’s new Wuhan, the original epicenter of the contagion.

Guangzhou is on a wartime footing amid the resurgence sparked by the Delta strain from India. Photo: China News Service

Xinhua quoted Guangzhou medical professionals treating delta variant cases as saying that shorter incubation periods, higher viral loads among patients and faster aggravation of severe conditions all make the new strain more dangerous than Wuhan’s initial strain of the disease.  

Some also suspect there is a gap between official caseload figures in Guangzhou and the actual situation on the ground.

One case in point is that asymptomatic carriers are not counted toward confirmed cases. The fact that the delta variant is still spreading in Guangzhou, almost a month into the city’s all-out mobilization and lockdowns, has raised concerns about the new variant’s staying power. 

In the neighboring city of Shenzhen, a new cluster was recently discovered at its sprawling airport after a health inspector contracted the delta strain after receiving an Air China plane from Johannesburg, South Africa, that was found to have 16 cases.

He is responsible for infections involving his wife, airport restaurant waiters and passengers at the airport subway station. Shenzhen and Dongguan officials are now scrambling to test a total of 8 million city and area residents.  

Now, airports and ports in Guangzhou and Shenzhen have started corralling international arrivals into standalone, fully sealed-off facilities for testing and checks amid calls to shut the border altogether and stop receiving foreign flights and ships. 

Mass testing of residents in Guangzhou with staff at some open-air testing centers facing torrential rain to collect samples. Photo: Xinhua
Guangzhou’s usually bustling CBD is deserted amid the latest outbreaks. Photo: WeChat

In a feature about the new strain, the state-backed Global Times has criticized rival India’s “sluggish, shambolic” response to its “avalanche of outbreaks” in previous months that unleashed the “monster strain” upon the world, just when the pandemic had started to abate in Asia and the West.

The nationalistic tabloid also cited Chinese Center for Disease Control (CDC) experts in a separate report as saying that even though etiological investigations in Guangzhou had yielded no results, the modest flare-up in southern China “has its ultimate origin in India.” 

At the same time, Chinese state media has until now played down the fact that a dozen infected patients in Guangzhou and Shenzhen had been fully inoculated with locally made vaccines, raising new questions about the efficacy of Sinovac and Sinopharm-made jabs. 

However, a Xinhua circular that appeared in almost all newspapers in China on Tuesday shifted focus to stress Chinese vaccines’ “outstanding” protection against severe complications and fatalities even though the shots may not protect people from catching the virus in the first place, particularly the more contagious delta strain. 

Feng Zijian, a senior Chinese CDC researcher, told Xinhua that “immune escape” and “breakthrough infections” had also been observed in the West where inoculated people succumbed to Covid-19. 

“Our data show that among the infected patients in Guangzhou and Shenzhen, those who have received jabs show far fewer occurrences of severe symptoms or conditions requiring immediate intervention, like using ventilators,” said Feng.

A nurse holds her arm after receiving the Sinovac vaccine in Hong Kong. Photo: AFP / Peter Parks

China had reputedly administered close to 1.4 billion doses nationwide as of Monday, with daily figures hitting 20 million since this month, according to a daily immunization tracker updated by the National Health Commission, which did not specify the number of those fully vaccinated.

China’s CDC recently set a higher herd immunity threshold of 85% of its 1.3 billion-plus population, higher than the internationally recommended 70%, seen by some as a tacit admission of the lower efficacy rates of Chinese shots vis-a-vis Western-made ones like Pfizer-BioNTech and Moderna’s. 

A recent University of Hong Kong comparison of antibody levels in groups inoculated with Chinese and Western vaccines showed that takers of BioNTech’s mRNA jabs show significantly higher antibody concentrations than those inoculated with Sinovac’s attenuated shots.

The research was commissioned by Hong Kong’s government. The city is among the few places where both Chinese and Western vaccines are rolled out for universal immunization. 

In a hint of the risks going forward, Chinese airlines and rail operators have been told to slash Beijing-bound departures from Guangzhou and Shenzhen to a minimum and tighten health inspection and control of arrivals, according to WeChat and Weibo posts. The Chinese capital is counting down to big public celebrations and parades to mark the centenary of the Communist Party on July 1.  

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