AstraZeneca (AZ) and Oxford University’s COVID-19 vaccine candidate AZD1222 has scored an average efficacy rate of 70% in an interim analysis of phase II/III trials conducted in the UK and Brazil.

This means that the jab, which comprises a modified version of a chimpanzee adenovirus, met the primary endpoint of the trials, demonstrating that it was ‘highly effective in preventing COVID-19’, AZ said in a statement.

The average efficacy rate was taken from two different dosing regimens, with one showing a better profile.

This includes one dosing regimen which showed vaccine efficacy of 90%, when AZD1222 was administered first as a half dose, followed by a full dose at least one month apart.

A second dosing regimen showed 62% efficacy when given as two full doses at least one month apart.

AZ added that it will continue to collect data and conduct additional analyses, which will further refine the efficacy reading and establish the duration of the protection.

“Today marks an important milestone in our fight against the pandemic. This vaccine’s efficacy and safety confirm that it will be highly effective against COVID-19 and will have an immediate impact on this public health emergency,” said Pascal Soriot, chief executive officer, AZ.

“Furthermore, the vaccine’s simple supply chain and our no-profit pledge and commitment to broad, equitable and timely access means it will be affordable and globally available, supplying hundreds of millions of doses on approval,” he added.

AZ is now preparing regulatory submissions of the data to global health authorities that can offer conditional or early approval for AZD1222.

The company is also seeking an emergency use listing from the World Health Organization (WHO) to fast-track access to vaccines in low-income countries.

Also this month, Pfizer/BioNTech and Moderna posted results from phase III trials of their own respective COVID-19 shots.

Pfizer/BioNTech’s mRNA-based shot, BNT162b2, demonstrated a 95% efficacy rate, while Moderna’s candidate mRNA-1273 scored 94.5% efficacy in phase III.