How long will vaccine mandates last for?

The Government has said that government departments can no longer hire unvaccinated staff, so the vaccine mandate applies to pretty much the entire state sector as well as retail and hospitality sectors etc.

This raises interesting questions. What happens in a few months when the vaccines reduce in effectiveness? Will public servants have to get a third booster shot or lose their jobs? Will cafe workers? Will teachers?

And what if annual booster shots are needed for years to come? Will people have to get an annual booster or have say 80% of jobs in New Zealand made off limits to them? And what will this do to social cohesion?