AstraZeneca has announced positive results for its Covid-19 vaccine in the primary analysis of the Phase 3 clinical trials from the UK, Brazil and South Africa.

The analysis showed that AstraZeneca Covid-19 vaccine, previously called AZD1222, is safe and effective in protecting against Covid-19, after more than 22 days from first dose.

The results published in The Lancet showed 76% efficacy for vaccine after a first dose, with protection maintained to the second dose.

The vaccine efficacy increased to 82%, with an inter-dose interval of 12 weeks or more.

Also, the analysis showed that the vaccine has potential to reduce asymptomatic transmission of the virus, based on weekly swabs obtained from volunteers in the UK trial.

The analysis was based on 17,177 participants accruing 332 symptomatic cases from the Phase 3 trial in UK, Brazil and South Africa, led by Oxford University and AstraZeneca.

AstraZeneca BioPharmaceuticals R&D executive vice president Mene Pangalos said: “This primary analysis reconfirms that our vaccine prevents severe disease and keeps people out of hospital.

“In addition, 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.”

Covid-19 Vaccine AstraZeneca authorised in 50 countries

Covid-19 Vaccine AstraZeneca was jointly developed by the University of Oxford and its spin-out company Vaccitech.

The vaccine leverages a replication-deficient chimpanzee viral vector, based on adenovirus containing genetic material of the SARS-CoV-2 virus spike protein.

AstraZeneca said that its Covid-19 vaccine has been granted a conditional marketing authorisation or emergency use in nearly 50 countries.

Oxford Vaccine Trial chief investigator professor Andrew Pollard: “These new data provide an important verification of the interim data that has helped regulators such as the MHRA in the UK and elsewhere around the world to grant the vaccine emergency use authorisation.

“It also helps to support the policy recommendation made by the Joint Committee on Vaccination and Immunisation for a 12-week prime-boost interval, as they look for the optimal approach to roll out, and reassures us that people are protected 22 days after a single dose of the vaccine.”