Changes to the Australian Vaccine Roll-out.
Blood Clot issues are affecting one in a million of the under 50s that would take the AstraZeneca version. This has caused a change to the Pfizer vaccine for most under 50s.
The European Union has blocked, or not yet approved, the exports of vaccines to certain countries, including Australia.
These two problems have, or will have, created delays in the Australian COVID-19 vaccine program.
It in now unlikely that the entire country will not be vaccinated by the end of the year, let alone by the end of October.