MIAMI (AP) — The Norwegian Cruise Line is seeking permission to resume trips from U.S. ports on July 4, requiring passengers and crew members to be vaccinated against COVID-19 at least two weeks before the trip.

The Miami company said its precautions go well beyond steps taken by others in the travel and leisure industry that have already reopened, including airlines, hotel, restaurants and sporting events.

Norwegian Cruise Line Holdings Ltd plans to begin U.S. sailings at 60% of capacity and raise that to 80% in August and 100% in September. Norwegian also operates Oceania Cruises and Regent Seven Seas Cruises.

Company shares rose less than 1% Monday. Shares of rivals Carnival Corp. and Royal Caribbean Group gained nearly 6% and more than 4%, respectively.

CEO Frank Del Rio detailed the request in a letter to Dr. Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention. The CDC has blocked cruise ships from U.S. ports with a no-sail order since March 2020, after outbreaks on several ships around the world.

On Friday, the CDC updated its guidance to say that fully vaccinated people can travel within the U.S. without getting tested for the coronavirus or going into quarantine afterward. It also issued more technical details around its conditional plan to allow cruise ships in U.S. ports, but it did not say when cruise lines could resume sailing.

Still, Walensky urged caution and said she would “advocate against general travel overall” given the rising number of infections.

The CDC did not respond immediately for comment Monday.

The Associated Press contributed to this report.