An analysis of Phase III clinical trials from the UK, Brazil, and South Africa confirmed that Covid-19 Vaccine AstraZeneca effectively prevents Covid-19, even with one dose.
The trials also showed that a second dose could be administered up to 12 weeks after the first. The Pfizer and Moderna vaccines in use in the U.S. have to administer with a month or so.
The longer time between doses would aid efforts to schedule vaccinations.
In addition to the three-nation program led by Oxford University, AstraZeneca is conducting a large trial in the US and globally. In total, Oxford University and AstraZeneca expect to enroll up to 60,000 participants.
AstraZeneca is expected to submit results to U.S regulators this spring.
The AstraZeneca vaccine is less expensive than the two currently approved vaccines and can be stored in refrigerators rather than freezers.
Results from the UK, Brazil, and South Africa showed vaccine effectiveness of 76 percent after a first dose, with protection maintained to the second dose. With an inter-dose interval of 12 weeks or more, vaccine efficacy increased to 82 percent. That figure compares favorably with Johnson & Johnson’s one-dose vaccine.
The analysis also showed the vaccine’s potential to reduce non-symptom transmission of the virus, based on weekly swabs obtained from volunteers in the UK trial.
The primary analysis for efficacy was based on 17,177 participant trials led by Oxford University and AstraZeneca.
Mene Pangalos, executive vice president of BioPharmaceuticals R&D, said: “This primary analysis reconfirms that our vaccine prevents severe disease and keeps people out of hospital. Also, extending the dosing interval not only boosts the vaccine’s efficacy but also enables more people to be vaccinated upfront. Together with the new findings on reduced transmission, we believe this vaccine will have a real impact on the pandemic.”
Data will continue to be analyzed and shared with regulators worldwide.
AstraZeneca is also seeking Emergency Use Listing from the World Health Organization for an accelerated pathway to vaccine availability in low-income countries.
AstraZeneca has administrative, logistics, and manufacturing operations in northern Delaware that employ 1,500.