Photo Credit: EQRoy / Shutterstock.com Norwegian Cruise Line Holdings has asked federal health authorities to let it sail from US ports starting July 4, the cruise line says its vaccination requirement for passengers and crew is a precaution against Covid-19. It cannot have been a shock that Norwegian Cruise Line announced a vaccine requirement for all cruises departing from the US, and for The third largest cruise line worldwide needs to sail, and adding the vaccinations to the onboard measures was a question of when not if one of the big three would require it. That being said, the question is now when and if Carnival and Royal Caribbean might require the same for when U.S. cruises resume. Although confidence in the vaccines has been low early on in the process, the number of Americans willing to get a shot is growing ever larger.