The Centers for Disease Control and Prevention (CDC) has rebuffed calls by the cruise industry to restart operations from U.S. ports, instead keeping current prohibitions in place through the summer travel season.

The CDC said Wednesday that restrictions placed on the cruise lines last year to counter the spread of the pandemic will remain in effect until Nov. 1. The statement comes just hours after a trade group representing the cruise industry called on the CDC to lift the restrictions and allow for the planning of a phased resumption of operations from U.S. ports beginning in July.

A cruise ship leaving port.

Image source: Getty Images.

Investors seem to have been expecting the CDC to follow the industry's advice, and that sent shares of Carnival (CCL -0.20%) (CUK -0.26%), Norwegian Cruise Line Holdings (NCLH -0.93%), and Royal Caribbean (RCL 1.60%) up more than 5% on Wednesday morning. The stocks gave back those gains after the CDC orders were made public.

On the surface, the industry seems to have a good argument to make. Airlines and other travel stocks have rallied so far in 2021 as vaccine rollouts have accelerated, and President Joe Biden earlier this month said he expects that by the July 4 holiday we'll see conditions normalize in the U.S.

"The cruise industry has adopted a high bar for resumption around the world with a multi-layered set of policies that is intended to be revised as conditions change," Kelly Craighead, president of the Cruise Lines International Association, said in a statement released prior to the CDC's announcement. "Cruise lines should be treated the same as other travel, tourism, hospitality, and entertainment sectors."

On its website, the CDC says that cruise passengers "are at increased risk of person-to-person spread of infectious diseases, including COVID-19, and outbreaks of COVID-19 have been reported on cruise ships."