What happened 

Shares of cruise line stock Carnival (CCL 0.61%) were down 3.3% today after new COVID-19 testing rules were announced. 

Some of the decline was likely due to the overall market falling. But there were some updated safety guidelines announced that couldn't have made investors happy. 

Cruise ship docked at a bay.

Image source: Getty Images.

So what 

The biggest news is that the U.S. Centers for Disease Control and Prevention recommends that passengers get a COVID test within two days of boarding a cruise ship, a shorter time frame than previous guidance. Here are some of the rules outlined by the CDC:

  • Vaccinated passengers need to get a PCR or rapid antigen test within two days of boarding a ship, or be tested on the day the cruise leaves. 
  • Unvaccinated passengers will need a PCR test within three days of boarding, a PCR or antigen test just before boarding, and another PCR or antigen test before debarking the ship. 
  • The CDC is also saying fully vaccinated passengers should wear masks, a reversal of May guidance that masks were not needed for vaccinated passengers. 

As cruise lines get back to a more regular operating cadence, this throws a wrench into their plans. Passengers now have to go through far more hoops, and that could deter people from taking a cruise

Carnival is running some cruises only for vaccinated guests, but these new rules, particularly around masking indoors, may deter some of these guests from wanting to go on a cruise at all. 

Now what

COVID variants are proving a difficult foe for the cruise line industry. The spread of COVID hasn't been contained, even in areas with high vaccination rates. And that's caused the CDC to recommend further restrictions on cruises, which is likely to at least reduce demand from customers. This is a pandemic that doesn't seem to be ending anytime soon, and that's a big reason Carnival's shares are down once again today.