Austria is the next country to offer 4th booster after Israel.

https://www.channelnewsasia.com/world/austrias-vaccine-board-recommends-fourth-covid-19-jab-some-2400296

Another country, Austria, will be offering 4th booster to its citizens.  It is looking increasingly likely that the full vaccination status will change to 4 vaccine doses instead of 3 doses in 2022.