COVID-19 vaccine developed by Oxford and AstraZeneca up to 90% effective, trial data show

London — And then there were three. U.K. pharmaceutical giant AstraZeneca, along with its partners at Oxford University, became on Monday the third team to announce positive late stage trial results for a COVID-19 vaccine. The "AZD1222" vaccine was "highly effective'' in preventing disease, with up to 90% efficacy in patients receiving one of the dose regimens used in trials, AstraZeneca announced.

The results are based on interim analysis of trials in the U.K. and Brazil of the vaccine developed by Oxford University and manufactured by AstraZeneca.  

"There were no hospitalizations or severe cases in anyone who had the Oxford vaccine, so that means that if we did have people vaccinated, so far the results imply that we'd be able to stop people getting severe disease and going into hospital," head of the Oxford Vaccine Group, Andrew Pollard, told BBC News.

U.K. Health Secretary Matt Hancock called it "fantastic news," noting that the trial data show "the vaccine in the right dosage can be up to 90% effective."  

The trial looked at two different dosing regimens — a half dose of the vaccine followed by a full dose at least one month apart was 90% effective. A second regimen using two full doses one month apart was 62% effective. The combined results showed an average efficacy rate of 70%.

"This vaccine's efficacy and safety confirm that it will be highly effective against COVID-19 and will have an immediate impact on this public health emergency,'' AstraZeneca CEO Pascal Soriot said. "Furthermore, the vaccine's simple supply chain and our no-profit pledge and commitment to broad, equitable and timely access means it will be affordable and globally available, supplying hundreds of millions of doses on approval."

Soriot said the finding that the vaccine appeared to work best when only a half-dose was given first was also good news, as it will increase the availability of the drug as soon as it's approved for use by regulatory agencies. 

"We can vaccinate more people faster," he told journalists on a group conference call after Monday's announcement. "That's really big for us." The company's executive vice president for operations, Pam Cheng, said on the conference call that AstraZeneca would have "approaching 200 million doses by the end of 2020, and more than 700 million doses by the end of Q1 globally."

Two other drugmakers, Pfizer and Moderna, last week reported results from late-stage trials showing that their COVID-19 vaccines were almost 95% effective. Pfizer became the first vaccine maker to seek emergency use authorization from the U.S. Food and Drug Administration on Friday.

The Oxford vaccine does not require storage at temperatures well below freezing, like the Pfizer formula, making it easier to distribute. It is also a cheaper vaccine to manufacture than the other two which have already shown high efficacy.

"Incredibly exciting news the Oxford vaccine has proved so effective in trials," U.K. Prime Minister Boris Johnson said in a tweet. "There are still further safety checks ahead, but these are fantastic results. Well done to our brilliant scientists at @UniofOxford & @AstraZeneca, and all who volunteered in the trials."

The Oxford vaccine news will be particularly welcome in Britain, not just because it was developed there, but because Johnson's government pre-ordered 100 million doses, or enough to treat 50 million people — more than half of the U.K. population of about 72 million.

The Trump administration was also an early investor in the Oxford-AstraZeneca partnership, committing up to $1.2 billion of American taxpayers' money in May to help develop the vaccine and secure up to 300 million doses of it.

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• AstraZeneca
• COVID-19
• Vaccines