(CN) — The creators of the Oxford-AstraZeneca vaccine say they envision their product as a global solution to the Covid-19 pandemic. New research on the vaccine’s efficacy suggests that researchers are inching toward that goal.
Analyzing clinical data from the United Kingdom, Brazil and South Africa, researchers report 76% efficacy for the AstraZeneca vaccine after a single dose, and 82% efficacy with a second dose, given 12 weeks later.
After participants were vaccinated, there were zero severe cases or hospitalizations, according to the report, which was preprinted Tuesday in The Lancet. The data also show that the AstraZeneca vaccine may reduce asymptomatic transmission of the novel coronavirus, based on a reduced number of positive swabs taken weekly from participants in the U.K. trial. Positive tests dropped 67% after a single dose and 50% after two, "supporting a substantial impact on transmission of the virus," the company said in a statement Wednesday.
Finally, the data also show that waiting 12 weeks or longer before administering a second dose increases the vaccine’s efficacy.
The study, which has not been peer-reviewed, expands upon previous data by including more cases from late-stage trials across three countries. It adds analyses of 201 symptomatic Covid-19 cases, for a total of 332 cases, and assesses a total of 17,177 study participants.
Sarah Gilbert, professor of vaccinology at the University of Oxford, led the research to design the vaccine candidate now licensed by AstraZeneca. During a Wednesday talk hosted by the New York Academy of Sciences, Gilbert said that as a university scientist, creating a vaccine to combat a pandemic should not center on the financial bottom line.
“We’ve been clear about the fact, from the beginning, that this was always going to be a vaccine for the world,” Gilbert said during live-streamed remarks. “It’s not just a vaccine that’s high-price and for high-income countries.”
Gilbert emphasized that trials could not be limited to the U.K. where they began if the goal is to create a vaccine that works for the entire planet. It's important to consider factors like human genetics, commensal pathogens and co-infections, which can vary based on where you live, she added.
“It was important to us from the beginning to be conducting clinical studies in different parts of the world,” Gilbert said.
In addition to studies in the three countries showing data in the new report, the Oxford-AstraZeneca team has begun a small early-stage trial in Kenya.
The new report not only clarifies the vaccine's efficacy, but also helps to inform rollout practices. In the U.K., the current policy is to give each dose 12 weeks apart.
The new report shows that a single dose is “highly efficacious” in the first 90 days, Gilbert said, “which provides further support for the policy of waiting 12 weeks to give the second dose, because there is no loss of protection between the first dose and the second.”
Unlike the Moderna and Pfizer vaccines approved in the United States, which require ultra-cold storage temperatures, the AstraZeneca version can be kept at normal refrigeration levels, specifically between 36 and 46 degrees Fahrenheit. Stored safely, it will keep for at least six months.
That’s promising for widespread distribution and getting doses to more remote areas of the world, where the cold supply chain may not easily reach.
AstraZeneca is seeking an OK for emergency use from the World Health Organization, to speed up distribution to low-income countries. Gilbert said her team plans to distribute 3 billion vaccine doses by the end of 2021, which will be manufactured by partners around the world.
Responding to calls for vaccine developers to share their intellectual property, “so that anybody can develop the same vaccine,” Gilbert stressed that building out facilities in partnership is necessary to ensure high quality.
Simply sharing IP “is not an approach that is ever going to be successful,” Gilbert said.
“It’s absolutely crucial that when the IP is shared, as part of a licensing arrangement, that comes with all the technical support that's needed to set up manufacturing of that vaccine, so that the quality is the same, the product is the same, and the results from the vaccine are going to be the same.”
She added that with complex manufacturing requirements, it’s not easy to scale up, and there have been some “teething problems” with lags in supply.
“It can take a few months to get yields up to the desired levels,” Gilbert said, but her team now sees higher production from longtime manufacturing partners, “now that they’ve really nailed down the process in their own facility.”
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