The aim of this paper is to use longitudinal data from the ninth wave of the ANU Impact Monitoring Survey program (collected in October 2021) to answer four key research questions related to vaccination in Australia: What are the factors associated with the relatively high vaccine uptake achieved in Australia? What are the remaining concerns for those who haven’t been vaccinated and can extra information shift these attitudes? What is the expected likelihood of individuals taking a booster or third-dose vaccine? and What are the factors associated with booster willingness?

Results confirm that vaccine rates are low in the states territories that did not experience significant lockdowns during the third wave of COVID-19 infections in Australia. Controlling for these differences, we also find that education and the socioeconomic status of the area in which a person lives to be the main determinant of vaccine uptake.

Side effects are now the overwhelming main concern for the remaining unvaccinated. An experiment using different types of information messages shows the importance of getting these right, as we find that they can have adverse effects on the attitudes among the remaining unvaccinated.

Focusing on boosters, we find that Australians are very willing to receive a COVID-19 booster when it is recommended for them to take one – 71.9 per cent of vaccinated adults say that they would definitely get a booster vaccine when recommended. Males, younger Australians, those who live outside of advantaged areas, those who have not completed Year 12, those who a language other than English, and those who have had their first dose vaccination relatively recently are all less willing to receive a booster vaccine. In a further information experiment we find that some message can have negative effects on the booster attitude.