AstraZeneca and the University of Oxford announced Monday that their inexpensive, easy-to-make coronavirus vaccine appears to be effective. This is the latest in a series of encouraging results from leading vaccine developers this month.
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 type of dosage.
While the vaccine’s overall effectiveness remains unclear, the encouraging preliminary results suggest it has the potential to become a powerful new weapon in the war on the pandemic, which has killed more than 1.3 million people worldwide since January and continues to do so still spread quickly.
AstraZeneca said it is expected to start distributing the vaccine this year and manufacture up to three billion doses next year. With two doses per person, this would be enough to vaccinate almost one in five people worldwide.
Unlike some other leading vaccine candidates, the AstraZeneca range can be manufactured in large quantities quickly, cost only a few dollars per dose, and are easy to store for long periods of time. This could significantly increase the number of countries and people who have access to the vaccine.
AstraZeneca’s announcement followed the publication of Pfizer and Moderna’s results, which showed that both vaccines are approximately 95 percent effective. However, these vaccines can only be kept outside of ultra-cold freezers for a few weeks, which makes their distribution and storage more difficult.
The $ 3 to $ 4 price of AstraZeneca’s shot is a fraction of the cost of some other vaccines. AstraZeneca has committed to offering it worldwide at cost until at least July 2021 and in poorer countries on a permanent basis.
The differences in effectiveness of the AstraZeneca vaccine reflected differences in the administration of doses in the late-stage studies. In the 90 percent effective dosing schedule, study participants received half a dose of the vaccine and a full dose one month later. The vaccine was less effective if people received a standard full dose in advance, followed by another full dose a month later. On average, the vaccine was 70 percent effective.
The analysis, which looked at data from participants from the UK and Brazil, did not reveal any serious safety issues that were confirmed to be related to the vaccine. It had been under scrutiny around the world after AstraZeneca temporarily halted its trials in September after a participant in the UK developed a neurological condition.
Oxford and AstraZeneca said they would submit the trial data to regulators in the UK, European Union and Brazil and obtain emergency clearance to start distributing the vaccine in those locations. British and European Union regulators have carried out so-called ongoing reviews of the vaccine, which could speed up the approval process.
The path to the availability of the vaccine in the US is less clear. Since clinical trials in the US have been suspended for more than a month, longer than in the UK and several other countries, US results are not expected until next year. And AstraZeneca didn’t test the more effective half-dose regimen in its US studies. The company announced that it is working with the Food and Drug Administration to include it in the ongoing study as soon as possible.
In the meantime, AstraZeneca said the company will release its latest UK and Brazilian trial data to the FDA this week. The company is seeking guidance on whether to officially submit the results for review and emergency approval, even though the US process is still ongoing.
Some experts said the FDA was unlikely to approve the vaccine without further data, especially since fewer than 2,800 participants in the clinical trials received the smaller first dose that produced such strong results. This is a much smaller sample size than the Pfizer and Moderna experiments.
“I don’t think the FDA had 3,000 participants as a basis for a decision,” said Dr. Eric Topol, clinical studies expert at Scripps Research in San Diego.
Pfizer and Moderna’s vaccines are based on a similar messenger RNA technology. It uses synthetic genetic material to stimulate cells to produce a harmless viral protein that can attack the immune system.
The AstraZeneca vaccine is different. It uses a weakened version of a chimpanzee adenovirus as a delivery vehicle to deliver coronavirus genes into human cells. This trains the immune system to fight future attacks by the actual coronavirus.
The company said its early analysis was based on 131 symptomatic coronavirus cases that occurred in participants at least two weeks after receiving their second shot.
None of the vaccinated people who developed the disease had to be hospitalized, AstraZeneca and Oxford said.
“Today is an important milestone in our fight against the pandemic,” said Pascal Soriot, managing director of AstraZeneca, in a statement. “The effectiveness and safety of this vaccine confirm that it will be highly effective against Covid-19 and have an immediate impact on this public health emergency.”
In a call to reporters Monday morning, the Oxford scientists said they were still trying to understand why the vaccine was more effective with a lower first dose. The first dose is designed to boost the immune system while the second is designed to boost the response.
Dr. Saad B. Omer, director of the Yale Institute for Global Health, pointed to several possible explanations as to why the dosage regimens produced different results. There could be significant differences between the two groups, such as: B. The age of the participants or their previous exposure to similar viruses that influenced their response.
The design of the vaccine could also play a role: the full dose could give participants immunity to the delivery vehicle and dampen their subsequent immune response. The sample size may also play a role. Because fewer participants received the smaller first dose, their results have less statistical power.
Dr. Omer cautioned against drawing any definitive conclusions until more details were available. “I would withhold my judgment until we specifically deal with more data,” he said.
Pam Cheng, executive vice president at AstraZeneca, told reporters Monday that the company should have four million cans available in the UK by the end of the year if it received regulatory approval. At least 300 million doses of the finished vaccine are expected to be distributed worldwide by the end of March.
Even without delays, however, the vaccine is still a long way from being widely available. Regulators need to evaluate the study data and decide whether to approve the vaccine. AstraZeneca needs to ramp up production and work with government officials to introduce cans. And for the first few weeks and months after the vaccine is approved, it is expected to be available only to the highest priority groups, likely health workers first, followed by other vulnerable groups.
Ms. Cheng said the half-dose regime would not complicate the supply chain significantly.
The FDA has announced that a Covid-19 vaccine will prevent disease or reduce its severity in at least half of the people vaccinated. This is similar to the effectiveness of seasonal flu vaccines in most years. Further interim results from other leading vaccine manufacturers, including Johnson & Johnson, are expected shortly.
The relatively simple storage requirements of AstraZeneca’s vaccine are expected to make adoption easier than some of the other leading vaccines. Moderna’s vaccine can be stored at the temperature of a regular refrigerator for up to a month. Pfizer’s can be stored in conventional freezers for up to five days or in special refrigerators for up to 15 days, but must otherwise be stored in ultra-cold conditions.
Andrew Pollard, the Oxford researcher in charge of the studies, told reporters Monday that the scientists’ goal was “to make sure we can have a vaccine that is widely available”. He added, “I think we actually did it.”
The data released on Monday comes from AstraZeneca’s Phase 2/3 clinical trial in the UK and the Phase 3 clinical trial in Brazil. Participants were randomly given either the coronavirus vaccine or a meningitis vaccine as a control, followed by a booster dose of the coronavirus vaccine, meningitis vaccine, or a placebo approximately four weeks later. Professor Pollard said the Oxford scientists were hoping to submit the results for publication in a peer-reviewed journal within 24 hours.
A vaccine that uses the technology behind AstraZeneca The candidate never received approval. However, the approach has been explored before, particularly in a small 2018 study of an experimental vaccine against the virus that causes Respiratory Syndrome in the Middle East (MERS). This virus is related to SARS-CoV-2, the novel coronavirus that causes Covid-19.
When Covid-19 surfaced, the Jenner Institute’s team of scientists in Oxford, which had led work on similar coronaviruses, had a head start. After the SARS-CoV-2 genetic code was released in early January, the Oxford team accelerated the adaptation of its platform to the new coronavirus and began animal testing.
They also needed a development and manufacturing partner and found one in AstraZeneca in April. Security testing began in the UK that month.
In May, the US Department of Health pledged up to $ 1.2 billion to fund AstraZeneca’s development and manufacture of the vaccine and secure at least 300 million doses if this proves effective. Department of Health and Human Services Secretary Alex M. Azar II described the deal as “an important milestone” in the work of Operation Warp Speed, the US government’s program to accelerate Covid-19 vaccines.
AstraZeneca has agreements to deliver doses of its vaccine, once approved, to other wealthy nations, including the UK and other nations in Europe, as well as to low and middle income countries. AstraZeneca vaccine is on track to deliver 44 percent of all doses to low- and middle-income countries and 33 percent of all doses worldwide, according to predictions from UK research firm Airfinity, which pursues business between vaccine makers and governments.
Jenny Gross contributed to the reporting.