New York, Sep 1 (IANS): The Covid-19 vaccine candidate developed by Oxford University in partnership with the UK-based global biopharmaceutical company AstraZeneca has reached Phase-3 trial in the US.

The trial will enroll approximately 30,000 adult volunteers at 80 sites in the US to evaluate if the candidate vaccine, known as AZD1222, can prevent symptomatic Covid-19, the US National Institutes of Health (NIH) said on Monday.

"Positive results from preclinical research led by NIH scientists supported the rapid development of this vaccine candidate, which has also showed promise in early-stage clinical trials," Anthony Fauci, Director of National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, said in a statement.

The Phase 3 trial is being implemented as part of Operation Warp Speed, a multi-agency collaboration led by the US Department of Health and Human Services that aims to accelerate the development, manufacturing and distribution of medical countermeasures for Covid-19.

The trial primarily is designed to determine if AZD1222 can prevent symptomatic Covid-19 after two doses. It also will evaluate if the vaccine candidate can prevent SARS-CoV-2 infection regardless of symptoms and if it can prevent severe Covid-19.

It also will assess if the experimental vaccine can reduce the incidence of emergency department visits due to Covid-19.

Participants are being randomised to receive two doses of either AZD1222 or a saline control, four weeks apart, with twice as many participants receiving the potential vaccine than the saline control.

Oxford University's Jenner Institute and Oxford Vaccine Group developed AZD1222. The candidate vaccine was licensed to AstraZeneca for further development.

The vaccine uses a non-replicating chimpanzee adenovirus to deliver a SARS-CoV-2 spike protein to induce an immune response.

SARS-CoV-2 is the virus that causes Covid-19.

AstraZeneca said it continues to engage with governments, multilateral organisations and partners around the world to ensure broad and equitable access to the vaccine, should clinical trials prove successful.

Recent supply announcements with Russia, South Korea, Japan, China, Latin America and Brazil take the global supply capacity towards three billion doses of the vaccine.

US President Donald Trump is pushing the Food and Drug Administration (FDA) to fast-track approval for Covid-19 treatments and vaccines.

In an interview with the Financial Times published on Sunday, FDA Commissioner Stephen Hahn said emergency authorisation of Covid-19 vaccine could be the right decision if the benefits outweigh the risks