The Silver Moon cruise ship in Greece for its christening last summer.
Silversea and Azamara are the latest cruise lines to require passengers to get a Covid-19 booster shot if they are eligible for one.
Starting with cruises departing March 1, both brands are requiring a Covid-19 booster.
Earlier this month, UnCruise Adventures said it would require boosters for eligible guests starting Feb. 5, and German luxe brand Hapag-Lloyd Cruises beginning Feb. 14.
Both Hapag-Lloyd and Silversea are owned by Royal Caribbean Group. Most lines, including Royal Caribbean International and Carnival Cruise Line, “strongly recommend” that passengers get boosters but do not require it.