http://www.newsweek.com/israel-approving-4th-vaccine-shot-1656291

Booster shots for COVID are increasingly being recommended amid the emergence of the Omicron variant in recent weeks and due to the effectiveness of vaccines waning over time.

For most people, a booster shot means a third dose of the COVID vaccine, but in Israel experts are already preparing to consider what might happen when protection from that third dose wanes.