Vaccine downgrade big setback
Hopes for quick shot for developing world diminish
Scientists in Brazil have downgraded the efficacy of a Chinese coronavirus vaccine that they hailed as a major triumph last week, diminishing hopes for a shot that could be quickly produced and easily distributed to help the developing world.
Officials at the Butantan Institute in Sao Paulo said that a trial conducted in Brazil showed that the CoronaVac vaccine, manufactured by the Beijing-based company Sinovac, had an efficacy rate just over 50 per cent. That rate, slightly above the benchmark that the World Health Organisation has said would make a vaccine effective for general use, was far below the 78 per cent level announced last week.
The implications could be significant for a vaccine that is crucial to China’s global health diplomacy. At least 10 countries have ordered more than 380 million doses of the Sinovac inoculation, CoronaVac, although regulatory agencies have yet to fully approve it.
A senior official in Hong Kong, which has already ordered CoronaVac, said yesterday that an advisory panel would strictly review the vaccine based on clinical trial data before it was rolled out there.
“Those countries that have ordered the Chinese-made vaccines are probably going to question the usefulness of these vaccines,” said Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations and an expert on healthcare in China. “Countries with opposition parties might use this to challenge the decision made by the incumbent government, and that will likely have domestic political implications in these countries,” Huang said.
Sinovac did not respond to multiple requests for comment.
For months, Chinese officials had said that the vaccines made by Sinovac and Sinopharm, a stateowned vaccine maker, would be important tools for fighting the pandemic in poorer countries that do not have extensive healthcare infrastructures. Unlike the vaccines made by US drugmakers Pfizer and Moderna, they do not need to be frozen.
The Oxford-AstraZeneca and Johnson & Johnson vaccines, which can be kept refrigerated and are more effective than their Chinese counterparts, could provide an alternative. But it is now unclear if the governments that have bought CoronaVac can scrap their deals and turn to others.
CoronaVac, unlike some of the other vaccines, relies on older technology that uses chemicals to weaken or kill the virus, which is then put into a vaccine to spark antibodies in the recipient. But the process of killing the virus can weaken a vaccine’s potency, resulting in an immune response that could be shorter or less effective.
The lower efficacy announced this week would mean it would take longer for countries that use CoronaVac’s vaccine to reach “herd immunity”, the point at which enough people are resistant to the virus — roughly 70 per cent, many scientists have said — that it is vanquished in a population. By contrast, the vaccines made by Moderna and
Pfizer-BioNTech have been shown to have an efficacy rate of about 95 per cent.
“This was one of the reasons the Americans and Europeans didn’t go with this older technology,” said John Moore, a vaccine expert at Cornell University. “A well-maintained Ford Model T would probably get you from Wuhan to Beijing, but personally I would prefer a Tesla.”
Brazil’s health regulatory agency, Anvisa, is reviewing data from the trial, which relied on volunteers who are healthcare professionals. If Anvisa approves emergency use of CoronaVac, officials hope to start giving out shots in Brazil late this
month. It has roughly 10.8 million doses of CoronaVac on hand. Last week, Brazil’s Health Minister, Eduardo Pazuello, said the Government intended to purchase 100 million doses of CoronaVac.
Natalia Pasternak, a microbiologist and the president of Instituto Questa˜o de Cieˆncia, a Brazilian nongovernmental organisation, told reporters that the results of the trial meant it would not be a panacea.
“It is not the best vaccine in the world,” she said at the news conference where the efficacy rate was disclosed.
But she called it a “perfectly acceptable vaccine” that would lead to fewer patients developing serious cases or dying from the virus.
Dimas Covas, the director of Butantan Institute, called the vaccine an “excellent” tool “waiting to be used in a country where currently 1000 people are dying per day”.
Many of the countries that have ordered CoronaVac are relatively poor, desperate to halt the pandemic and protect their populations.
Indonesia, for example, has ordered 125.5 million CoronaVac doses. The country has reported nearly 850,000 coronavirus cases and nearly 25,000 deaths, the highest numbers in Southeast Asia.
In the short term, some countries may have few viable vaccine options.
Governments, many of them in richer nations, have already locked in more than half the doses that could come onto the market by the end of next year.
To its comparative advantage, Sinovac has immense manufacturing capacity. The company has said it can make 600 million doses this year.
In China, the weaker efficacy data from Brazil could be a setback for the country’s biotech ambitions.
It had pinned its hopes on making a Covid-19 vaccine that would burnish its credentials as a global scientific power.
The tepid results could also be problematic for Chinese officials, given that they had touted the efficacy of the vaccines made by Sinovac and Sinopharm.
Even though the vaccines had not received regulatory approval, and data from late-stage trials had not been made public, Beijing gave them to thousands of Chinese people under an emergency use policy; it plans to vaccinate 50 million people by the middle of next month.