China ‘cannot relax coronavirus controls’ amid threat from Delta variant

Health official says authorities will continue to focus on preventing imported cases from spreading locally after recent outbreaks
Limited data on how well vaccines work against highly infectious strain but expert says ‘partial protection is better than no protection’

Coronavirus pandemic

Holly Chik

Published: 8:30pm, 9 Jul 2021

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China has signalled it has no plans to lower its guard against Covid-19 as the threat posed by the highly transmissible Delta variant increases.

Li Bin, vice-minister of the National Health Commission, said authorities would continue to focus on preventing imported infections from spreading locally and strengthen inspection of imported goods.

“Some cities have recently seen local clusters caused by imported cases of the Delta variant, including Guangzhou, Shenzhen and Ruili,” he told reporters in Beijing on Thursday. “These waves have reminded us that we cannot relax our pandemic control measures.”

Ruili, a city on the border with Myanmar, went into lockdown on Wednesday as authorities try to keep a lid on China’s latest outbreak of Covid-19, which has been linked to the Delta strain.

The Delta variant, first discovered in India and circulating in more than 100 countries, is estimated to be 55 per cent more transmissible than the Alpha variant first found in Britain, according to the World Health Organization.

“Even the Delta variant itself is mutating and it will continue to do so. We still have the upper hand. Let’s use the tools that we have to keep transmission down,” Maria Van Kerkhove, the WHO’s technical lead on Covid-19, told reporters on Wednesday.

02:03

Chinese city on Myanmar border in Covid-19 lockdown amid fears of the spread of Delta variant

One of the main tools is vaccines. In China, more than 1.3 billion jabs had been administered as of Thursday – or more than 90 doses per 100 people. Most of the Covid-19 vaccines approved for use in the country require two doses.

The Chinese vaccine made by Sinovac Biotech has become the most used in the world, and has been shown to protect against the disease and hospitalisation in clinical and real-world studies. But little data is available about how well it stands up against the Delta variant.

Immunologist Ashley St John, an associate professor at Duke-NUS Medical School in Singapore, said it was important to understand how different vaccines worked against variants, but data was still limited. “There are already plans for updating vaccines to include the Delta strain, and it’s possible that certain vaccines may need a boost to ensure optimal protection to emerging variants,” she said.

“Importantly the vaccines can protect the individuals who take them from severe disease and even if there is partial protection to the Delta variant, this is better than no protection at all.”

07:07

The global spread of the highly contagious Delta variant of Covid-19

Pfizer and BioNTech are developing an updated version of their vaccine to target the full spike protein of the Delta variant, the companies said on Thursday. The first batch of the mRNA for the trial has already been manufactured and clinical studies are expected to begin in August.

The companies said that while they believed a third shot of their two-dose vaccine “has the potential to preserve the highest levels of protective efficacy against all currently tested variants including Delta”, they remained vigilant and would continue to update the jab.

Now for the big Covid-19 test: how well do vaccines work in the real world?

It follows a study in the US that found the blood serum from people given two doses of the Pfizer/BioNTech vaccine could neutralise new variants including Delta, according to a paper published in the journal Nature in June.

A separate study in France found that the Delta variant could escape neutralisation from one dose of the Pfizer or AstraZeneca vaccines or antibodies produced from previous infection, highlighting the need to get fully vaccinated, researchers said in a paper, also in Nature, in July.

“Our neutralisation experiments indicate that Pfizer and AstraZeneca vaccine-elicited antibodies are efficacious against variant Delta, but about three- to fivefold less potent than against variant Alpha,” the scientists said.

The Delta variant could also make it harder for countries to reach herd immunity. In Australia, for example, modelling suggests that at least 85 per cent of the population has to be vaccinated.

“[Herd] immunity has become more difficult to achieve with the Delta variant, as it is both more infectious and less amenable to vaccination,” said Emma McBryde, a professor of infectious diseases epidemiology and modelling at James Cook University in Queensland.

Additional reporting by Simone McCarthy

This article appeared in the South China Morning Post print edition as: Mainland rules out easing of curbs amid Delta threat