Astrazeneca COVID-19 vaccine backed by governments despite questions over efficacy

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Britain and several other countries are standing by the Oxford-AstraZeneca vaccine despite questions about its effectiveness against the South African variant of the virus that causes COVID-19.

British Prime Minister Boris Johnson said the government was “very confident” in all of the vaccines currently in use. “It’s important for people to bear in mind that all of them, we think, are effective in delivering a high degree of protection against serious illness and death, which is the most important thing,” Mr. Johnson said Monday.

Health ministers in France, Germany and Australia also expressed confidence in the vaccine. “The AstraZeneca vaccine reinforces and amplifies our vaccination strategy,” French Health Minister Olivier Véran said Monday.

Canada has ordered up to 20 million doses of the vaccine. However, Health Canada has yet to approve it.

The countries made their comments in response to a study released on the weekend that showed the vaccine provided 22-per-cent protection against mild and moderate cases of the South African variant. The trial involved 2,026 volunteers in South Africa with an average age of 31. There was no indication as to how effective the vaccine was in preventing severe illness and further research is under way.

The South African variant surfaced in December and it is considered up to 50 per cent more contagious than the original version of the virus. It is now the dominant variant in South Africa and it has spread to several other countries, including Canada.

The test results are a setback for the British government, which has bet heavily on the vaccine, a joint venture between the University of Oxford and British-Swedish drug giant AstraZeneca. The government invested £88-million ($154-million) in developing the vaccine and Britain was the first country to authorize its use.

On Monday, health officials played down the South African results and said the vaccine had proved to be highly effective against the British variant of the virus, which is now dominant in Britain.

Jonathan Van-Tam, the Deputy Chief Medical Officer for England, said there were only 147 cases of the South African variant in Britain and it was unlikely to overtake the British mutation any time soon. He added that he expected the Oxford-AstraZeneca vaccine will prove to be effective in preventing severe illness from the South African variant and that even if it didn’t, it could be altered and administered as a booster shot. “The stories and headlines around variant viruses and vaccines are a bit scary and I wish they weren’t,” he said Monday.

Nonetheless, the South African test results could be a blow to the global rollout of the vaccine. The Oxford-AstraZeneca vaccine has been touted as less expensive and easier to use than other vaccines, making it especially attractive for developing countries.

The COVAX program, a multinational organization designed to help poor countries buy vaccines, has made the Oxford AstraZeneca vaccine the centrepiece of its program and ordered 350 million doses. COVAX officials said Monday they may have to reassess their plans but they still had confidence in the vaccine.

“At the moment at least, it looks like the AstraZeneca vaccine is an efficacious vaccine,” said Seth Berkley, who heads Gavi, an alliance of business and non-profit groups that’s part of COVAX. “It has been reviewed by a number of stringent regulatory authorities and gotten approval and had studies in many countries.”

Health officials in South Africa have already said they will scale back their use of the vaccine. The government had planned to launch it next week across much of the country. However, they will now introduce it in stages in order to monitor its effectiveness.

“We don’t want to end up with a situation where we’ve vaccinated one million people or two million people with a vaccine that may not be effective in preventing hospitalization and severe disease,” Salim Abdool Karim, the co-chair of South Africa’s Ministerial Advisory Committee on COVID-19, told a press conference on Monday.

Dr. Karim said laboratory tests have been completed on five vaccines in use or under development, including Oxford-AstraZeneca’s. “What they show is that vaccine-induced antibodies have greater difficulty neutralizing the [South African] variant than they have against pre-existing variants,” he said.

He added that further clinical trials on three of the vaccines – from Novavax, Johnson & Johnson and Oxford-AstraZeneca – found that Oxford-AstraZeneca fared the worst against the South African variant. “While the overall efficacy of the AstraZeneca vaccine was 66 per cent in the larger study that included the U.K., Brazil and South Africa, the South African data on its own showed only 22-per-cent efficacy,” he said.

The South African government now plans to inoculate around 100,000 people at first and monitor hospitalization rates. If rates are low, Dr. Karim said the vaccine will be rolled out on a wider scale. If they aren’t, ”We will need to look at alternatives.”

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