This is incorrect.Well this sux.
CDC level 4 = DCL will return to US port if one (1) case shows up onboard.
Imagine going on a 14-night or even a 7-night and on day#2 someone gets the bug and ship has to return to port and the entire itinerary is cancelled.
It's 99% likely there will be at least 1 Covid-related case onboard based on a ship with 4000 ppl.
Does the CDC not realize that even with vaccines being 99% effective, that's 40 ppl statistically likely to get the virus?
Gosh this is a huge buzzkill.
CDC hasn't defined a 'one case' threshold anywhere. It's a threshold based on each ship's occupancy and size, and we won't know anything about it until the ship get its certificate.