Health & Fit: AstraZeneca, Oxford say their vaccine is up to 90% effective

With AstraZeneca's vaccine trial still on pause in US, questions abound about study participants' mysterious illnesses

  With AstraZeneca's vaccine trial still on pause in US, questions abound about study participants' mysterious illnesses As US health authorities consider whether to allow AstraZeneca to resume the clinical trial of its coronavirus vaccine, crucial questions remain about neurological illnesses suffered by study participants who received injections of the experimental vaccine. © The Lundquist Institute/FILE A man receives an injection as UCLA and AstraZeneca begin phase three trials in a potential COVID-19 vaccine.

AstraZeneca and the University of Oxford announced on Monday that their inexpensive, easy-to-produce coronavirus vaccine appears effective , the latest in a string of encouraging results this month from leading vaccine developers. An early analysis of data from late-stage clinical trials found that AstraZeneca ’s vaccine was either 62 percent or 90 percent effective , depending on the manner in which the doses were given. AstraZeneca said it expected to begin distributing the vaccine this year and that it would be able to make up to three billion doses next year.

Oxford and AstraZeneca say their COVID-19 vaccine works too. The vaccine may be easier to distribute than those from Pfizer and Moderna. A COVID-19 vaccine made by AstraZeneca and the University of Oxford appears to prevent illness and may cut down on transmission of the coronavirus. In studies of more than 22,000 people in the United Kingdom and Brazil, the vaccine was 90 percent effective in preventing COVID-19 when people got a half dose of the vaccine followed by a full dose one month later, AstraZeneca said November 23 in a news release.

U.K.-based pharmaceutical giant AstraZeneca and England's University of Oxford announced Monday that late-stage trials show their COVID-19 vaccine was up to 90% effective in preventing the disease.

A volunteer receives an injection at the Chris Hani Baragwanath Hospital in Johannesburg, South Africa, on June 24, 2020, as part of Africa's first participation in the AstraZeneca/Oxford COVID-19 vaccine trial. © Siphiwe Sibeko/Pool via AP A volunteer receives an injection at the Chris Hani Baragwanath Hospital in Johannesburg, South Africa, on June 24, 2020, as part of Africa's first participation in the AstraZeneca/Oxford COVID-19 vaccine trial.

The results are based on interim analysis of phase 3 trials in the United Kingdom and Brazil, which looked at two different dosing regimens. One regimen showed vaccine efficacy of 90% when the drug, called AZD1222, was given as a half dose, followed by a full dose at least one month apart. A second regimen showed 62% efficacy when given as two full doses at least one month apart. The combined analysis from both dosing regimens showed an average efficacy of 70%, according to press releases from AstraZeneca and Oxford.

Why Oxford-AstraZeneca COVID Vaccine Could Be More Important Than Pfizer and Moderna's in Ending Pandemic

  Why Oxford-AstraZeneca COVID Vaccine Could Be More Important Than Pfizer and Moderna's in Ending Pandemic "We have a vaccine for the world," said Professor Andrew Pollard from the University of Oxford. So, how does it compare to other contenders? What are its other advantages? And who might get it first?On Monday, AstraZeneca and Oxford announced interim data from its large Phase III trial indicated that its vaccine candidate is "effective at preventing COVID-19 and offers a high level of protection.

Oxford - AstraZeneca announces COVID-19 vaccine that is up to 90 % effective and can be stored in a normal fridge - and America has already bought 300m doses. The British drugmaker is the third major drug company to report late-stage results for a potential COVID-19 vaccine . Pfizer and Moderna last week reported preliminary results from late-stage trials showing their vaccines were almost 95% effective . Unlike its rivals, however, the AstraZeneca vaccine doesn't have to be stored at ultra-cold temperatures, which makes it easier to distribute.

Astra and Oxford 's vaccine candidate shows average 70% efficacy in two regimens. Developing economies dependent on vaccine since it's cheaper, doesn't require ultra-cold. 9.6 billion vaccine doses have been purchased, mainly by high income countries. After both Pfizer/BioNTech and Moderna's coronavirus vaccines showed over 95% effectiveness in interim analysis, AstraZeneca and Oxford University announced their AZD1222 vaccine showed an average efficacy of 70% in early results from late-stage trials in the U.K. and Brazil.

There were a total of 131 COVID-19 cases in the analysis, and no hospitalizations or severe cases of the disease were reported in participants receiving the vaccine candidate, according to the press releases.

"These findings show that we have an effective vaccine that will save many lives," Andrew Pollard, director of the Oxford Vaccine Group and chief investigator of the Oxford vaccine trial, said in a statement Monday. "Excitingly, we’ve found that one of our dosing regimens may be around 90% effective and if this dosing regime is used, more people could be vaccinated with planned vaccine supply."

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Researchers were, however, surprised that the lower dosing regimen proved more successful, with Pollard describing these results as "intriguing" during a press conference Monday.

AstraZeneca Oxford vaccine is 70% effective on average, data shows

  AstraZeneca Oxford vaccine is 70% effective on average, data shows Drugmaker AstraZeneca announced on Monday that its experimental coronavirus vaccine has shown an average efficacy of 70% in large scale trials -- the latest of several vaccine trials worldwide to post their results this month. © Siphiwe Sibeko/AP FILE - In this Wednesday, June 24, 2020 file photo, a volunteer receives an injection at the Chris Hani Baragwanath hospital in Soweto, Johannesburg, as part of Africa's first participation in a COVID-19 vaccine trial developed at the University of Oxford in Britain in conjunction with the pharmaceutical company AstraZeneca. On Friday, Oct. 23, 2020, AstraZeneca Inc.

The drug maker said its vaccine candidate was 70 percent effective on average, and potentially up to 90 percent effective , at preventing Covid-19 in an early analysis. The company said its early analysis was based on 131 coronavirus cases that turned up among participants at least two weeks after they had received their second shot. In the trial in Britain, researchers counted infections by swabbing participants weekly. That detection method was likely to have turned up more infections than the trials run by Moderna and Pfizer, which tested people who developed symptoms and may have

Password. Forgotten account? Sign Up . AstraZeneca and Oxford scientists say their COVID-19 vaccine is up to 90 % effective .

"We think that by giving a smaller first dose that we’re priming the immune system differently," he explained. "We’re setting it up better to respond."

​Dr. Carlos del Rio, an infectious diseases expert at Emory University who was not involved in the research, told ABC News it's plausible that the different responses could be due to a "prime-boost phenomenon," which may be more common among vaccines that use viral vector technology, like AZD1222.

a close up of a hand holding a blue object: In this undated photo issued by the University of Oxford, a researcher in a laboratory at the Jenner Institute works in Oxford, England, works on the COVID-19 vaccine developed by AstraZeneca and the University of Oxford. © University of Oxford/John Cairns via AP In this undated photo issued by the University of Oxford, a researcher in a laboratory at the Jenner Institute works in Oxford, England, works on the COVID-19 vaccine developed by AstraZeneca and the University of Oxford.

Sarah Gilbert, professor of vaccinology at the University of Oxford and another one of the lead scientists involved with the trial, said that while more analysis was needed, one hypothesis could be that this particular dosing regimen better mimics the body’s natural response to an infection.

AstraZeneca and Oxford University's vaccine is effective at preventing COVID-19, trial results suggest. Here's everything we know so far.

  AstraZeneca and Oxford University's vaccine is effective at preventing COVID-19, trial results suggest. Here's everything we know so far. AstraZeneca and The University of Oxford's covid-19 vaccine is 70% effective, the groups say. Here's everything we know about the vaccine so far.The results follow months of trials of more than 20,000 volunteers in the UK, Brazil, and South Africa, and showed that the vaccine stopped people from developing any COVID-19 symptoms in 70% of the cases on average.

U.K.-based pharmaceutical giant AstraZeneca and England's University of Oxford announced Monday that late-stage trials show their COVID-19 vaccine was up to 90 % effective in preventing the disease.

"It could be that by giving a small amount of the vaccine to start with and following up with a bigger amount, that’s a better way of kicking the immune system into action and giving us the strongest immune response and the most effective immune response," Gilbert said at Monday's press conference.

AstraZeneca, which has promised not to profit from the vaccine "for the duration of the pandemic," said it will now immediately prepare to submit the data to regulators around the world -- including in the United Kingdom, Europe and Brazil -- that have framework in place for conditional or early approval. The Oxford and AstraZeneca teams are hopeful of swift approvals, as many regulators have been reviewing the trial data on a rolling basis. The British drugmaker said it will also seek an emergency use listing from the World Health Organization for an accelerated pathway to vaccine availability in low-income nations.

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Meanwhile, Oxford said it is submitting the full analysis of the interim results for independent scientific peer review and publication.

"Today marks an important milestone in our fight against the pandemic," AstraZeneca CEO Pascal Soriot said in a statement Monday. "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."

a group of men sitting at a table in front of a store: A laboratory technician supervises capped vials during filling and packaging tests for the large-scale production and supply of the AstraZeneca/Oxford COVID-19 vaccine candidate at a manufacturing facility in Anagni, Italy, on Sept. 11, 2020. © Vincenzo Pinto/AFP via Getty Images A laboratory technician supervises capped vials during filling and packaging tests for the large-scale production and supply of the AstraZeneca/Oxford COVID-19 vaccine candidate at a manufacturing facility in Anagni, Italy, on Sept. 11, 2020.

Clinical trials of AZD1222 are also being conducted in the United States, Japan, Russia, South Africa, Kenya and Latin America, with planned studies in other European and Asian countries. In total, AstraZeneca said it expects to enroll up to 60,000 participants globally. The results from these trials will better help demonstrate the durability of the vaccine candidate and how effective it is against transmission. Although details were not published in Monday's press release, Gilbert told reporters that preliminary data shows a reduction in the number of asymptomatic infections.

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"That’s really going to make a big difference to transmission," Gilbert said, adding that there's also an early indication the drug could help prevent severe disease.

"It’s preliminary data, we need to follow up more," she noted, "but it looks like this vaccine is working against severe disease because we don’t have any hospitalizations and severe cases in any of the groups that got vaccinated."

Despite these significant steps, AZD1222 will not be available in the United States any time soon. The trials there were halted while a potentially adverse reaction was investigated, making them a step behind in data collection. Also, AstraZeneca will now have to seek approval from the U.S. Food and Drug Administration to change their trial protocol to incorporate this new lower dose followed by a higher dose regimen.

"Our plan would be to incorporate another arm into the study that would test the half dose/full dose regimen into the trial and we would set them up within weeks," Mene Pangalos, AstraZeneca's executive vice president of biopharmaceuticals research and development, told reporters during a virtual briefing Monday.

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When asked by ABC News if AstraZeneca faced a possible scenario that their vaccine would be available around the world while still pending FDA approval in the United States, Pangalos confirmed it was a possibility.

"We will work out what the most appropriate next steps are," he said, adding that the company will be talking to the FDA this week to firm up their plans. "Our job now is as rapidly as possible to work with regulators around the world to see this vaccine approved and then hopefully implemented."

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AstraZeneca sees AZD1222 as a game-changer because it will be comparatively easy to distribute.

"I have little doubt that this vaccine is going to have a big impact around the world in terms of getting the pandemic under control and will help us all return to a sense of normality," Pangalos told reporters.

A volunteer receives an injection at the Chris Hani Baragwanath Hospital in Johannesburg, South Africa, on June 24, 2020, as part of Africa's first participation in the AstraZeneca/Oxford COVID-19 vaccine trial. © Siphiwe Sibeko/Pool via AP A volunteer receives an injection at the Chris Hani Baragwanath Hospital in Johannesburg, South Africa, on June 24, 2020, as part of Africa's first participation in the AstraZeneca/Oxford COVID-19 vaccine trial.

AstraZeneca's leadership is bullish on plans to distribute the vaccine globally. In Monday's press release, the company said it is "making rapid progress in manufacturing" and expects to produce up to 3 billion doses of AZD1222 in 2021 on a rolling basis, pending regulatory approval. The drug can be stored, transported and handled at normal refrigerated conditions for at least six months and administered within existing health care settings.

Alongside their international partners, AstraZeneca plans to distribute all 3 billion doses worldwide by the end of 2021 and, according to Monday’s press release, "already has international agreements in place" to supply those doses, "with access being built through more than 30 supply agreements and partner networks."

"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.

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Dr. Adrian Hill, a vaccinologist and the director of the University of Oxford’s Jenner Institute, which co-developed AZD1222, said he is "delighted with these results."

"The efficacy level is very high," Hill told ABC News in an interview Monday. "We are seeing protection not just against clinical disease, which was the primary endpoint, but strong evidence that there is going to be good efficacy against severe disease and hospitalization. We have nobody in the vaccination group who was admitted to hospital, and there's even evidence that we may well be protecting against transmission, which is a first for the field."

When asked about the two different immunization approaches that were tested in the trials, Hill said it's "very unlikely" the one with the 90% efficacy is a chance finding.

"There were thousands of people in [the trial]," he said. "The efficacy was highly statistically significant."

Because the trials involved more than 24,000 participants in the United Kingdom, South Africa and Brazil, experts said the vaccine's safety has been tested on an ethically diverse group, which Hill said is "what you would need to provide a global vaccine." Hill noted that AZD1222 could become available in the United Kingdom in the first quarter of 2021.

The U.K. government has already placed orders for 100 million doses of the AstraZeneca/Oxford vaccine candidate, along with 40 million doses of another developed by Pfizer and BioNTech, which uses a different technology called mRNA and has shown in a phase 3 trial to have 95% efficacy with no serious safety concerns to date.

Pfizer and BioNTech announced Friday that they had submitted a request to the FDA for emergency use authorization of their COVID-19 vaccine candidate.

ABC News' Sony Salzman and Sohel Uddin contributed to this report.

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