The mean reported efficacy of 70% was significantly lower than the 94.5% to 95% reported by the other two main candidates, Moderna and Pfizer.
« [T]he vaccine Pfizer has made a commitment to send its initial doses to the EU and the United States. And Moderna’s supply will be tied to the United States for at least likely the first half of 2021, so in light of that, the Oxford / AstraZeneca vaccine is very good news for the rest of the world, ”Andrea Taylor, Deputy Director of programs at the Duke Global Health Innovation Center, told CNN.
Oxford / AstraZeneca vaccine can be stored at refrigerator temperatures of 2 to 8 degrees Celsius (36 to 46 degrees Fahrenheit) for at least six months. Moderna vaccine should be stored at -20 ° C (-4 ° F) – or refrigerator temperature for up to 30 days – and Pfizer / BioNTech vaccine should be stored at -75 ° C (-103 ° F ) and used once within five days. refrigerated at higher temperatures.
“Pfizer and Moderna require freezer storage, which is just not in place in many settings,” Ghani said.
“Cold chain” refrigeration is the standard storage used around the world to deliver vaccines from central sites to local health centers. AstraZeneca’s vaccine is so far “the only one that can be definitively delivered to these systems,” Ghani added.
Vaccines are based on different technologies. AstraZeneca’s offering – like the vaccine from Johnson & Johnson and Russia’s Sputnik V – uses an adenovirus to transport genetic fragments of the coronavirus around the body.
Moderna and Pfizer vaccines use pieces of genetic material called messenger RNA (mRNA) to trick the body to make synthetic pieces of the coronavirus and stimulate an immune response. “This is a relatively new technology and little is known about the stability of mRNA over time,” said Penny Ward, chair of the medical school’s education and standards committee. UK Pharmaceuticals, to CNN.
She said Moderna and Pfizer accumulate information and manufacturing capabilities, they may be able to find methods of storage at higher temperatures, but the Oxford vaccine “has the potential to be able to be more easily shipped worldwide” using the chains of existing supply.
However, it will only be useful if the vaccine’s efficacy levels are maintained during its distribution in developing countries.
AstraZeneca said this week that trials showed that one dosage regimen produced 62% effectiveness while the other reached 90%, an average of 70%. That’s a good result, comparable to the flu shot, but not as high as Pfizer’s 95% and Moderna’s 94.5%. The 90% figure is based on a sample of 2,741 participants, which is a relatively small number.
Moncef Slaoui, chief advisor to the US government’s Operation Warp Speed, said this week that there were “a number of variables we need to understand” around the differences in dosage and age in the results. from Oxford / AstraZeneca, after which the current US test may need to be changed.
On Thursday, an AstraZeneca spokesperson told CNN that they are currently in talks with the FDA to include the half-strength dosage regimen in their U.S. trials, which currently have around 10,000 participants.
Ayfer Ali, associate professor of international business at Warwick Business School, said the AstraZeneca vaccine’s “ease of distribution” could “possibly outweigh any potential efficacy.”
“The actual efficacy of mRNA vaccines which are more fragile to transport and store may be lower under real conditions where the correct storage of each dose may be difficult to verify,” she added.
BioNTech said last week that it is working with Pfizer to come up with a formulation that would allow its vaccine to be stored at standard temperatures by the second half of 2021. Moderna this month extended its estimate of how long her vaccine could remain stable at refrigerator temperature for about seven to 30 days. This, according to Juan Andres, Director of Technical Operations and Quality at Moderna, “would allow for simpler distribution and more flexibility to facilitate larger scale vaccination in the United States and other parts of the world.”
Commit to help
AstraZeneca has pledged 300 million doses of its vaccine to COVAX, a partnership between GAVI, the vaccine alliance; the World Health Organization; and the Coalition for Epidemic Preparedness Innovations (CEPI) to ensure equitable distribution in 92 developing countries. The only other known vaccine developer to commit to a similar scale is Sanofi, at 200 million doses.
A representative from GAVI told CNN that the Serum Institute of India (SII) and the Bill and Melinda Gates Foundation will also provide up to 200 million doses of vaccine candidate AstraZeneca and / or Novavax to low-income countries. Moderna and Pfizer have not promised COVAX any doses.
This could mean that AstraZeneca has more manufacturing capacity than other pharmaceuticals thanks to its links with industry giants such as SII through CEPI.
« [AstraZeneca has] worked with manufacturing experts from this coalition to help find a variety of different manufacturing sites, and of course, it’s not just the vaccine itself, it’s also the glass vials it goes into, the caps that are on the bottles and the syringes and needles, ”Ward said.
AstraZeneca says it expects to be able to produce up to 3 billion doses of the vaccine in 2021 on an ongoing basis. Pfizer / BioNTech says it can manufacture up to 50 million doses in 2020 and 1.3 billion in 2021, while Moderna says it expects to be able to deliver around 500 million doses per year and possibly up to 1 billion doses per year from 2021.
After calls for transparency from groups such as Medicins Sans Frontieres and Global Justice Now, AstraZeneca and Oxford confirmed that the partnership will deliver the vaccine on a non-profit basis until at least July 2021 worldwide, and to perpetuity at low and middle income. countries.
The Oxford vaccine is cheaper than the others, at around $ 3 to $ 4 per dose, compared to around $ 20 for the Pfizer vaccine and $ 32 to $ 37 for the Moderna vaccine.
“Our vaccine can be rapidly deployed in existing health facilities, which will help stop the spread of this disease while learning more and more about how to prevent and treat it,” said a spokesperson for Oxford University to CNN. He added that a range of vaccines would be needed and some might be more effective for different ages and populations.
“The key to any vaccine is the potential for public health impact, including how quickly it can be distributed. Ours can be quickly and easily distributed around the world, using existing logistics, and easily stored in a refrigerator, ”he said.
COVAX will be critical in getting the vaccine to low- and middle-income countries, as modeling from Duke University shows. The initiative aims to deliver 2 billion doses by the end of 2021 to protect high-risk groups around the world and eventually enough doses to cover 20% of the population of these countries.
However, Ghani warned that 20% was “far from the ideal – around 70% – which we would like to see in order to be able to get collective immunity, so some countries will still fall short.”
She said it was vital for everyone that the world’s population be vaccinated, to allow movement and movement across borders. Deployment of the vaccine worldwide could take until 2023, according to current models – not to mention the potential need for booster vaccines.
“Access to safe and effective COVID-19 vaccines for the most vulnerable groups all over the world is the only way to bring the acute phase of this pandemic under control,” said Dr Seth Berkley, CEO of Gavi, welcoming the news about the Oxford vaccine in a statement this week.
Duke’s modeling shows that if richer countries bought billions of doses up front to increase their chances of covering their populations, the developing world will be completely dependent on COVAX.
Bill Gates said the solution “does not shame rich countries that are doing the natural thing to want to protect their people” but was to dramatically increase manufacturing capacity.
Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, warned that monitoring efficacy and safety concerns would be an ongoing challenge in developing countries.
“There may be unwanted effects that would only be apparent in these low- and middle-income countries; they have different diets, they have different levels of nutrition in general and different characteristics, ”he told CNN.
While the Oxford vaccine may hold particular promise at this point in helping low-income countries, there are still many caveats about the data that must be resolved before it can be deployed.
Ultimately, it will be vital to have as many vaccines as possible, to ensure faster recovery and limit further damage to the world.
CNN’s Harry Clarke-Ezzidio, Jen Christensen, Maggie Fox and Kara Fox contributed reporting.