Covid 19 coronavirus: AstraZeneca says US trial data shows vaccine 79 per cent effective

Scientists have been waiting for results of the US study in hopes they will clear up some of the confusion about how well AstraZeneca's Covid vaccine really works. Photo / AP

AstraZeneca says advanced trial data from a US study on its Covid vaccine shows it is 79 per cent effective.

The US study comprised 30,000 volunteers, 20,000 of whom were given the vaccine while the rest got dummy shots. The results were announced today.

The early findings from the US study are just one set of information AstraZeneca must submit to the Food and Drug Administration.

An FDA advisory committee will publicly debate the evidence behind the shots before it decides whether to allow emergency use of the vaccine in the US.

While the AstraZeneca vaccine has been authorised in more than 50 countries worldwide, scientists have been awaiting results of the US study in hopes they will clear up some of the confusion about just how well the shots really work.

New Zealand has agreements with four suppliers for Covid-19 vaccines: Pfizer/BioNTech, Janssen Pharmaceutica, Novavax and AstraZeneca.

In early March, the Government announced it had secured additional doses of the Pfizer vaccine, bringing its total to 10 million doses - enough to fully vaccinate every New Zealander.

Based on data provided by the manufacturer, the Pfizer-BioNTech vaccine has been shown to be 95 per cent effective in an ongoing large-scale clinical trial.