Oxford vaccine dosage ‘mistake’ led to 90% efficacy finding

Vaccination in Australia could start in March, pending TGA approval, according to the Minister for Health

A dosage mistake has led to the Oxford COVID-19 vaccine achieving 90% efficacy in phase 3 trials and triggered its plan to seek regulatory approval including in Australia.

In what the researchers called a case of serendipity, the first of two doses of the vaccine candidate given to more than 2700 participants in the UK phase 3 trial was half-strength.

Oxford University’s commercial partner AstraZeneca on Monday unveiled interim trial results showing 90% efficacy in the UK group compared with 62% efficacy among participants who received two full doses in a trial in Brazil.

“Yes, it was a mistake,” Sir Mene Pangalos (PhD), head of non-oncology research and development at AstraZeneca, conceded.