Doubts over efficacy of Chinese vaccines stoke anxiety at home and abroad

The Omicron variant of coronavirus forced governments across the world to tighten border controls, hasten vaccination drives and reinstate social distancing last week. But in Dalian, China, authorities reclassified the virus risk in parts of the north-eastern port city from “medium” to “low”.

The contrast, Chinese health officials and experts said, reflected how Beijing’s unwavering zero-Covid policy had proven a “magic bullet”, preventing at least 200m infections and 3m deaths. Western hubris, they argued, had led to negligence and now the potentially destabilising Omicron outbreak.

“Western countries are likely to be gripped by Omicron if the variant proves highly infectious, with their unscientific easing of epidemic control measures and overconfidence in vaccines,” reported the Global Times, a nationalist news service.

State media crowing, however, belied uncertainty in the minds of many in China over the efficacy and durability of immunity of the country’s locally produced vaccines as Beijing rolls out booster shots and inoculations for children as young as three.

Doubt over the jabs matter not only for the world’s most populous country, where 2.5bn doses have been administered to 1.4bn people. They also matter to the hundreds of millions of people who have received vaccines made by Sinovac and Sinopharm — both of which use an inactivated vaccine rather than the genetic code used by mRNA vaccines such as BioNTech/Pfizer and Moderna.

Ben Cowling, a professor of epidemiology at the University of Hong Kong, said there was “still a lot more uncertainty about the effectiveness of inactivated vaccines compared to some of the other vaccines being widely used, like the two mRNA vaccines and the AstraZeneca vaccine”.

China’s recent Delta outbreak — which spread to more than half the country’s provinces and prompted local lockdowns — indicated that the effectiveness of the Chinese-made vaccines “against infection and transmission can’t be that high because very stringent public health measures were still needed to control those outbreaks”, said Cowling.

But the outbreak also suggested “vaccine effectiveness against severe Covid-19 appears to be high because the recent outbreaks have included very few severe cases”.

The Omicron variant, which has rapidly spread as far as London, New York and Seoul, presents vaccines with a new test.

According to the first detailed study by South African epidemiologists, Omicron has been linked to a substantial rise in coronavirus reinfections compared with previous waves.

In many poorer countries, China’s vaccines were critical to saving lives early in the pandemic after a Covax vaccine initiative under Gavi, a UN-backed alliance, struggled to hit its distribution targets. Despite the pace and scale of the rollout, uncertainty over the vaccines has persisted in China and abroad.

This has in part been caused by the Chinese government. Since the coronavirus was first discovered in Wuhan almost two years ago, Beijing’s censors have quashed any signs of dissent or questioning of the state’s response.

The lack of transparency over the jab’s efficacy and waning durability has worried many Chinese, particularly parents of young children and the elderly. According to interviews and private social media chat groups seen by the Financial Times, parents have over recent months quietly sought to resist giving consent for their children’s shots.

Latin America and the Caribbean, home to barely 8 per cent of the world’s population, have suffered close to one-third of all Covid-related deaths. While China has delivered almost twice the number of vaccines as the US — most of which were distributed via Covax — countries are increasingly switching to other manufacturers.

The Brazilian state of São Paulo forged a partnership with Sinovac last year, just as President Jair Bolsonaro was facing criticism for his government’s response to the pandemic. The Chinese-developed vaccine accounted for most injections in the early stages of the inoculation campaign in Latin America’s most populous country but has since been overtaken by the Oxford/AstraZeneca jab.

São Paulo officials initially claimed CoronaVac, the vaccine produced by Sinovac, showed 78 per cent efficacy against mild to severe cases in local trials. But following criticism over a lack of data transparency, scientists announced days later that the overall rate was only 50.4 per cent — just above the threshold required for regulatory approval — once “very mild” cases were included.

Researchers from the state’s Butantan Institute, which fills and finishes CoronaVac vaccines in Brazil, have since said, with a space of 21 days or more between two doses, efficacy could reach 62.3 per cent. But doubts have been raised about the length of immunity.

Butantan has supplied more than 100m doses of CoronaVac, the majority of which were manufactured from its own facilities. However, there are no further contracts for domestic provision or any negotiations with the federal government, said the institute.

In Singapore last week, the health ministry said that people who received two doses of the Sinovac or Sinopharm vaccine would need a third dose from next month to be considered “fully vaccinated”.

While China’s vaccines appear to be falling out of favour, the speed of Beijing’s vaccine diplomacy will not be so easily undone.

“They [the Chinese] took advantage of a tactical window and they’ve pressed other geostrategic priorities — [the acceptance of] Huawei [network technology], Taiwan recognition,” said Daniel Runde, at the Center for Strategic and International Studies, a US think-tank.

Many health experts have also warned that politics is hampering scientific co-operation and discussions in response to the pandemic, especially between the west and China.

Jerome Kim, an immunology expert and director-general of the UN’s International Vaccine Institute who has worked with both Chinese and western vaccine developers, warns that jabs are not a solution in themselves.

“Globally, we have seen the effectiveness of vaccination, yet infections, disease and death from Covid-19 remain,” he said.

“Have we forgotten that vaccines are typically most effective as part of a systematic approach to prevention, an approach that for Covid-19 still includes masks, distancing, crowd avoidance, isolation, testing and booster injections?”

Additional reporting by Maiqi Ding in Beijing and Mercedes Ruehl in Singapore