This week Indonesia overtook India as Asia’s COVID-19 epicentre. The nation posted 56, 757 new cases on Thursday, more than five times the number reported a month ago.
The crisis has overwhelmed Indonesia’s health system in many areas and is undermining hard-won economic progress. It also offers the world a frightening example of how the delta strain can kill vaccinated people.
Unlike India, which initially approved the AstraZeneca and its home-grown Covaxin vaccines, Indonesia has largely relied on the CoronaVac vaccine developed by the Chinese company Sinovac Biotech.
Indonesia’s policy of prioritising healthcare workers meant the majority had received two doses of CoronaVac before the delta variant became the dominant strain across the country. But as increasing numbers of fully vaccinated doctors became seriously ill – at least 20 are known to have died and the country’s doctors association said the true number is much higher – Indonesia has made changes to its vaccine policy.
It’s now racing to give 1.47 million workers a booster shot of the Moderna vaccine, and desperately hoping it can secure more non-Sinovac product through multilateral deals such as Covax.
The Sinovac vaccine – like the other widely used Chinese vaccine BIBP, developed by Sinopharm – exposes the body’s immune system to a modified form of the virus to trigger the production of antibodies. Pfizer and Moderna vaccines are mRNA vaccines that trigger an immune response without using a live virus.
Elsewhere in south-east Asia, Thailand is also changing tack. A week ago the government announced 618 of 677,348 health workers who received two doses of Sinovac had tested positive for COVID-19 All of those workers are now also in line for a booster, in this case AstraZeneca. Other Thais who have had a single dose of Sinovac can now choose to have AstraZeneca for their second jab.
A leaked document detailing the minutes at which a booster shot was discussed in Bangkok revealed some participants worried about the message it would send. It would be tantamount admitting Sinovac was ineffective, they thought.
This is not true, epidemiologists say, noting that some protection is better than none. Many more Indonesian doctors would likely have died if they had remained unvaccinated, and substandard personal protection gear is also thought to have played a role in the deaths.
But while vaccines are generally holding the line against serious infections – as demonstrated in Britain – it appears Sinovac at times may not be as effective against new strains. Delta has become the dominant variant in many countries because it so infectious. Scientists say it is also possible the mutations it carries could weaken the fighting ability of the antibodies and immune cells that vaccinated people typically develop.
South America’s lambda variant
Away from Asia, there is speculation another variant may have “learnt” the same trick. The lambda variant was identified last year in Peru and has been reported in 20 countries. A month ago it was identified as a variant of interest by the World Health Organisation. A study by researchers from the University of Chile, yet to be peer reviewed, notes the lambda variant has seven mutations, one of which, L452Q, is similar to the L452R mutation found in the delta and epsilon variants – and which, the researchers say, has been shown to confer “immune escape”.
“Together, our data revealed that the spike protein of the newly recognised variant of interest, Lambda, highly circulating in Chile and South American countries, carries mutations conferring increased infectivity and the ability to escape from neutralising antibodies elicited by CoronaVac,” the paper’s authors conclude.
Professor Thomas Preiss, a molecular biologist at the Australian National University, says most virus variants quietly disappear because they don’t “perform” as well as the original.
“But occasionally a variant will acquire some advantage, and then it will eventually outcompete the original virus,” he says. “Causing more serious disease isn’t typically to the virus’ advantage, but an increased ability to infect new people is.
“This advantage could come about in multiple ways and it would depend on the circumstances. For example, the variant virus’ spike protein could bind more strongly to receptors on target cells. That’s what seems to have now happened repeatedly as it ‘faced’ largely unvaccinated populations but with some public health measures in place to prevent transmission.
“In the context of a largely vaccinated population, selective pressure could give rise to virus variants that better evade recognition by the immune system of vaccinated people, which was ‘pre-trained’ only on the original virus.
“How strongly might that reduce vaccine protection? Well, it depends on how much the interaction of spike protein and antibody is weakened, but equally on how quick and strong the immune response ramps up in response to the initial infection,” Priess says.
The strength and speed of the immune response depends on the type of vaccine used and on how it was administered. “Faster vaccination campaigns that reach ‘herd immunity’ quicker will give the virus less opportunity to evolve”, Priess says.
Balancing the political minefield of offending China’s thin-skinned Communist regime against the urgent realities of a global health crisis is a major challenge for countries still reliant on Chinese vaccines, which are the most widely-used in the world.
The Chinese vaccines are effective but imperfect. For those who have no access to any other vaccines, they can still play a role.
— Jin Dong-yan, University of Hong Kong professor
Chinese officials don’t appear to be concerned about the efficacy of Sinovac and Sinopharm’s vaccines against the delta variant. The vaccine developers have said they are studying COVID-19 variants, but admit this is difficult to do in mainland China where there is little data because a zero-tolerance approach towards the pandemic has kept infection rates low – for now.
Foreign vaccines are not yet available in mainland China, where 1.3 billion doses of locally made vaccines have been administered. China wants 80 per cent of its 1.4 billion people vaccinated by the end of the year.
A refusal to acknowledge the risks, which will make it harder for China to reopen its borders, is a potential threat to one of the few Asian countries that has avoided repeated waves of outbreaks with strict lockdowns, travel restrictions and extensive contact tracing.
“The Chinese vaccines are effective but imperfect. For those who have no access to any other vaccines, the imperfect vaccines can still play a role. It is better than nothing. To some extent they are still saving lives,” Jin Dong-yan, a professor at the University of Hong Kong’s school of biomedical science, told AFR Weekend.
“On the other hand, the Chinese vaccines are 50 to 60 per cent effective initially, so if this goes down below the 50 per cent threshold set by the WHO … there’s a problem.”
Jin says there are three solutions to make the Chinese vaccines more effective against variants such as delta: increase the dose, add a third injection, or use it with a combination of other vaccines.
New mRNA vaccine
While China has imported doses of the mRNA vaccine developed by Germany’s BioNTech and China’s Fosun Pharma, it has not yet been approved for use. Chinese media outlet Caixin reported on Thursday that Chinese regulators have completed an expert review of the vaccine and the shot is in the administration review stage,
“I strongly appeal for them to quickly approve the BioNTech vaccine so China will be safer. They require the trial to be done in China, but there is no COVID in China so I don’t know how they can do the trial. It is a political issue,” Jin says.
In Hong Kong, residents have a choice of both Western and Chinese-made vaccines, but many say they feel protected with Sinovac. “I feel somewhat protected compared to people who haven’t had it. I am not worried it is less effective as long as I have my masks and sanitary routine and am aware of who I am with,” says Miss Wong, a 30-year-old marketing executive.
Sinovac says it has conducted research on the delta variant, although it has not released details. “What we found is that the current vaccines can neutralise these variants ... Inactivated vaccines have good neutralising effect,” Sinovac chief executive Yin Weidong told Chinese new agency Xinhua last month, in comments that appear to contradict the concerns coming out of Indonesia and Thailand.
“Through the industrial layout of our research in COVID-19 vaccine and the completed clinical research, the efficiency of vaccine research in mutant strains will be greatly improved,” Yin said. “Once the virus mutates, we can quickly produce a vaccine with the mutated strain.”
Sinovac has not released any vaccine effectiveness results against the delta variant based on large-scale data.
China’s top epidemiologist, Zhong Nanshan, last month appeared to admit he was worried the country’s existing hotel quarantine system could not cope with highly transmissible variants. He made the comments to journalists when outlining plans to build a huge quarantine complex in Guangzhou for international travellers from high-risk countries.
Staying ahead of the virus mutations remains a major challenge, not just for China but for all countries. Lack of data, the rapidly changing nature of the virus, the challenge of distributing vaccines in poorer countries, and political bickering are ongoing obstacles.
Jin says he has not given up, though. “I think we should stay positive, stay optimistic. The UK data shows the fatalities are very low and close to the seasonal flu. It is still not impossible to eradicate the virus from the human population, but the future of the pandemic depends on the countries where the outbreak is controlled most poorly – because they could still spread it to other places.”