Here's the Australian Technical Advisory Group on Immunisation post from when Australia discontinued AstraZeneca for people aged under 60 (and made Pfizer the preferred vaccine instead):
From early April to 16 June 2021, 60 cases of confirmed or probable TTS [thrombosis and thrombocytopenia syndrome] have been reported in Australia. This includes an additional seven cases reported in the past week in people between 50-59 years, increasing the rate in this age group from 1.9 to 2.7 per 100,000 AstraZeneca vaccine doses.... TTS is a serious condition in a proportion of individuals who develop it. The overall case fatality rate in Australia (3%; 2 deaths among 60 cases) is lower than has been reported internationally.
