Oxford University and AstraZeneca became the first Covid-19 vaccine makers to publish final-stage clinical trial results in a scientific journal Tuesday, clearing a key hurdle in the global race to develop safe and effective drugs for the new coronavirus.

The study published in the respected Lancet medical journal confirmed that the vaccine works in an average 70 percent of cases, with efficacy of 62 percent for those given two full doses, and of 90 percent in those given a half then a full dose.

The results are the "first full peer-reviewed efficacy results" published for a Covid-19 vaccine, the Lancet said.