Australia unable to get extra Pfizer vaccine Share The nation's top doctor says it has not been feasible to secure more supplies of drug giant Pfizer's coronavirus vaccine despite negotiations, as he rebuffed calls to pause the rollout of the AstraZeneca vaccine because it will be less effective than others. With the Morrison government planning to begin rolling out Pfizer's vaccine next month to an eventual five million recipients, Chief Medical Officer Paul Kelly has defended Australia's reliance on AstraZeneca's version of the vaccine to immunise the bulk of the population. Australia's Chief Medical Officer Paul Kelly says the government has not found it feasible to order extra doses of Pfizer's vaccine.