AstraZeneca has announced positive results from the primary analysis of the Phase 3 US clinical trial of its Covid-19 vaccine AZD1222.

In a recent interim analysis, AZD1222 demonstrated 79% vaccine efficacy against symptomatic Covid-19, 100% efficacy against severe or critical Covid-19 and hospitalisation.

The primary analysis confirmed that the vaccine showed 76% efficacy against symptomatic Covid-19 after 15 days from receiving two doses, which was the primary endpoint.

Also, the vaccine showed 100% efficacy in preventing severe Covid-19 and hospitalisation, which is a key secondary endpoint. It showed 85% vaccine efficacy in people aged 65 years and above.

AstraZeneca said that the AZD1222 well tolerated in all 190 cases in the primary analysis, without any safety concerns identified.

AstraZeneca biopharmaceuticals R&D executive vice president Mene Pangalos said: “The primary analysis is consistent with our previously released interim analysis, and confirms that our Covid-19 vaccine is highly effective in adults, including those aged 65 years and over.

“We look forward to filing our regulatory submission for Emergency Use Authorization in the US and preparing for the rollout of millions of doses across America.”

The Phase 3 clinical trial, dubbed D8110C00001, evaluated the safety, efficacy, and immunogenicity of its Covid-19 vaccine AZD1222 in 32,449 participants in the US.

The primary analysis was based on 190 symptomatic Covid-19 cases accumulated from the Phase 3 study, along with 49 cases from the previously announced interim analysis.

The UK drugmaker said that the primary analysis confirmed that the vaccine efficacy is consistent with the previously announced interim analysis.

Also, data from the primary analysis of the Phase 3 trial have been presented to the independent Data Safety Monitoring Board.

The UK company intends to use the primary analysis data for the regulatory submission to the US Food and Drug Administration (FDA) for Emergency Use Authorisation.