Expert commentary: Oxford and AstraZeneca vaccine preliminary Phase III data

The University of Oxford and AstraZeneca have announced interim data from their Phase III trials of their COVID-19 vaccine candidate, ChAdOx1 nCoV-2019.

Their interim analysis shows the candidate is, on average, 70.4 per cent effective at preventing COVID-19 when combining data from two dosing regimens.

CSIRO’s expert Dr Rob Grenfell comments on the news.

CSIRO Health and Biosecurity Director, Dr Rob Grenfell

It’s very encouraging to see that in the higher efficacy dose regimen, a combination of a half dose followed by a full dose resulted in 90 per cent efficacy against the disease.

At a time where demand for vaccines far outstrips supply, using one and a half doses rather than two means Australia’s supply of the Oxford-AstraZeneca candidate will go much further.

The interim data shows the vaccine reduced asymptomatic infections, and there were no severe cases or hospitalisations among those who received the vaccine.

It’s also important to see that the vaccine demonstrated a strong immune response in older people, a key high-risk group in this pandemic.

CSIRO is pleased to have been able to play a role in the validation of this vaccine through pre-clinical testing at our Australian Centre for Disease Preparedness earlier this year.

As part of CSIRO’s preclinical trial of Oxford-AstraZeneca’s candidate, our scientists evaluated the efficacy of one versus two doses as well as administration of the vaccine via a nasal delivery and/or an intramuscular injection.

This is hopeful news as biotechnology company CSL started manufacturing the vaccine candidate in Victoria on 9 November 2020.

Phase III trials are conducted in large populations in current disease outbreak sites where the virus is in high circulation. While it’s important to remember these are provisional results that haven’t been peer reviewed, these interim results bring us another step closer to defeating the novel coronavirus and seeing a safe and efficacious vaccine delivered in Australia and around the world.

Read more about Oxford University’s interim trial news.

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