News by Nathan Vass, Zoe Smith, Maria Bervanakis, David Aidone 13th Jan 2021 8:39 AM Premium Content Subscriber only Herd immunity against COVID cannot be achieved in Australia with the lower-Âefficacy Oxford-AstraZeneca Âvaccine, which the Morrison government plans to administer to millions of Australians, according to leading doctors. Medics and infectious disease experts are calling for Australia to invest in more high-efficacy vaccines, rather than relying on the ÂAstraZeneca jab. Australia has ordered 53.8 million doses of the AstraZeneca vaccines which has been shown in trials to have a much lower level of efficacy than Pfizer and Moderna vaccines being injected in Britain, France, Israel and the US,