The results are based on an interim analysis of trials in the UK and Brazil. No hospitalizations or serious cases of COVID-19 were reported in those who received the vaccine.
Australian Health Minister Greg Hunt issued a statement saying he was delighted with the news and that Australians could receive the vaccine in March.
“I was briefed on this evening by the Australian CEO, who confirmed that AstraZeneca is now looking to proceed with Australia’s regulatory approval in the coming weeks, if not sooner,” Hunt said.
“Subject to approval, this means that Australians are very well on their way to the first vaccines in March.”
Unlike the Pfizer and Moderna vaccines, the Oxford-AstraZeneca candidate does not have to be stored in extremely cold temperatures, making it easy to distribute, especially in developing countries. All three vaccines must be approved by regulators before they can be widely distributed.
“Oxford vaccine can be stored in the refrigerator, as opposed to the freezer like the other two vaccines, which means it is a more practical solution for use around the world,” said Peter Horby, Professor of Emerging Infectious Diseases and Health. Global at Oxford.
The results come as a second wave of COVID-19 hits many countries, again closing businesses, restricting social interaction and hitting the global economy.
AstraZeneca said it will immediately apply for early approval of the vaccine when possible, and will seek an emergency use list from the World Health Organization, to make the vaccine available in low-income countries.
The AstraZeneca trial looked at two different dosing regimens. A half dose of the vaccine followed by a full dose at least one month later was 90% effective. Another approach, giving patients two full doses one month apart, was 62% effective. The combined results showed an average efficacy rate of 70 percent.
The vaccine uses a weakened version of a common cold virus that is combined with genetic material for the characteristic spike protein of the virus that causes COVID-19. After vaccination, the spike protein prepares the immune system to attack the virus if it later infects the body.
Peter Openshaw, professor of experimental medicine at Imperial College London, said the finding that a smaller starting dose is more effective than a larger one is good news because it can lower costs and mean more people can get vaccinated.
“The report that a starting half dose is better than a full dose seems contradictory to those of us who think of vaccines as normal drugs: With drugs, we expect higher doses to have greater effects and more side effects,” he said. “But the immune system doesn’t work like that.”
The results reported Monday come from trials in the UK and Brazil involving 23,000 people. Late-stage trials are also underway in the US, Japan, Russia, South Africa, Kenya, and Latin America, with additional trials planned for other European and Asian countries.
AstraZeneca has been increasing manufacturing capacity, so it can supply hundreds of millions of doses of the vaccine starting in January, CEO Pascal Soriot said earlier this month.
Soriot said Monday that the simpler supply chain for the Oxford vaccine and AstraZeneca’s commitment to providing it on a non-profit basis during the pandemic mean it will be affordable and available to people around the world.
“The efficacy and safety of this vaccine confirm that it will be very effective against COVID-19 and will have an immediate impact on this public health emergency,” Soriot said.
British Health Secretary Matt Hancock said he felt “a great sense of relief” at the AstraZeneca news.
Britain has ordered 100 million doses of the Oxford vaccine, and the government says several million doses can be produced before the end of the year if regulators approve it.
Just a few months ago, “the idea that by November we would have three vaccines, all of which are highly effective … I would have given up,” Hancock said.