AstraZeneca has unveiled interim safety and efficacy data from the Phase 3 clinical trial of its Covid-19 vaccine candidate, AZD1222, conducted in the US.

In the interim analysis, AZD1222 showed 79% vaccine efficacy against symptomatic disease and 100% efficacy against severe Covid-19 and hospitalisation.

The interim analysis was based on 32,449 participants accruing 141 symptomatic cases of Covid-19, across 88 sites in the US, Chile and Peru.

AZD1222 leverages a replication-deficient chimpanzee viral vector based on adenovirus that contains the genetic material of the SARS-CoV-2 virus spike protein.

The vaccine can be stored, transported and used at normal refrigerated conditions for a minimum of six months, and prevents the need for preparation within existing healthcare settings.

AstraZeneca biopharmaceuticals R&D executive vice-president Mene Pangalos said: “These results add to the growing body of evidence that shows this vaccine is well tolerated and highly effective against all severities of Covid-19 and across all age groups.

“We are confident this vaccine can play an important role in protecting millions of people worldwide against this lethal virus.

“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 Authorisation.”

Last year, AstraZeneca has expanded the clinical development of its Covid-19 vaccine candidate in the US, with a Phase 3 clinical trial.

In the Phase 3 trial, participants randomised to receive AZD1222 were administered two doses of vaccine, at an interval of four weeks.

The UK drugmaker said that an independent data safety monitoring board (DSMB) has identified no safety concerns related to the vaccine, and was well tolerated.

After reviewing the thrombotic events, along with cerebral venous sinus thrombosis (CVST) with help of an independent neurologist, the DSMB found no increased risk of thrombosis or events characterised by thrombosis.

Phase 3 trial co-lead principal investigator Ann Falsey said: “These findings reconfirm previous results observed in AZD1222 trials across all adult populations but it’s exciting to see similar efficacy results in people over 65 for the first time.

“This analysis validates the AstraZeneca Covid-19 vaccine as a much-needed additional vaccination option, offering confidence that adults of all ages can benefit from protection against the virus.”

Furthermore, the company intends to submit its primary analysis to the US Food and Drug Administration (FDA) for Emergency Use Authorisation (EUA).