The US-based Phase III trial of AstraZeneca’s (AZ) vaccine – AZD1222 – has demonstrated a vaccine efficacy of 79% at preventing symptomatic COVID-19.

In addition, the jab was also found to have 100% efficacy at preventing severe disease and hospitalisation in the late-stage study.

This efficacy was consistent across ethnicity and age – in participants aged 65 years and over demonstrating the vaccine efficacy was 80%.

AZ added that the vaccine was well tolerated, with no safety concerns related to the vaccine highlighted by the independent data safety monitoring committee (DSMB).

The DSMB also conducted a specific review of thrombotic events and cerebral venous sinus thrombosis (CVST).

They found no increased risk of thrombosis or events characterised by thrombosis among the 21,583 participants who had received at least one dose of the vaccine, with no CVST events found in the trial.

The US Phase III trial included two doses administered at a four week interval, however previous trials have shown that an extended interval of up to 12 weeks demonstrated greater efficacy.

“We are confident this vaccine can play an important role in protecting millions of people worldwide against this lethal virus,” said Mene Pangalos, executive vice president, BioPharmaceuticals R&D, AZ.

“We are preparing to submit these findings to the US Food and Drug Administration and for the rollout of millions of doses across America should the vaccine be granted US Emergency Use,” he added.