The last time I ferreted out on the longevity of the antibodies, whether naturally acquired or vaccinated, is estimated at 8 months. Even Oz Health admits to not knowing:
'It is not yet known how long the protection afforded by a COVID-19 vaccine will last. This is being evaluated in ongoing research.
Most COVID-19 vaccines require two doses. This includes the Oxford/AstraZeneca vaccine, the Pfizer vaccine and the Novavax vaccine. Whether you will need additional booster doses, such as an annual booster, for COVID-19 vaccines is still being determined by ongoing clinical trials."
