RELATED: Virus Experts Have Stopped Going to These 4 Places as Delta Surges. In an update released on Aug. 20, the health agency changed its current travel risk level for cruises to “Level 3: High” and recommended that seniors should avoid them, regardless of their vaccination status. It also specified that vaccinated people who are pregnant, were recently pregnant, anyone with “an increased risk of severe illness,” and people of any age who are unvaccinated shouldn’t board a cruise ship for the time being. “The virus that causes COVID-19 spreads easily between people in close quarters aboard ships, and the chance of getting COVID-19 on cruise ships is high,” the CDC wrote on its website. The CDC update also specified that while it wasn’t issuing a mask mandate for cruise ships similar to the one in place for travel on airplanes, trains, buses, and other public transportation, it now recommends that any passengers should wear a face-covering whenever in public spaces onboard the vessels. However, the agency noted that “individual cruise lines may require travelers (passengers and crew) to wear masks indoors on board the ship.” RELATED: Don’t Eat Indoors If You Live Here—Even If You’re Vaccinated, Virus Expert Warns. The agency now recommends that anyone boarding a cruise ship should get tested for COVID-19 one to three days before their voyage and then again three to five days after they return, even if they’re fully vaccinated. It also suggests that anyone who is unvaccinated should self-quarantine for seven days when they return from their cruise, even if they test negative. The change in guidance comes after a spate of recent COVID-19 infections have been reported on cruises. Last week, 27 fully vaccinated people aboard a Carnival cruise ship docked in Belize tested positive for the virus. And in July, four vaccinated adult passengers and two unvaccinated children aboard a Royal Caribbean ship tested positive during a courtesy end-of-cruise screening, USA Today reports.ae0fcc31ae342fd3a1346ebb1f342fcb RELATED: For more up-to-date information, sign up for our daily newsletter. “The health, safety, and well-being of our guests, crew, and the destinations we visit is our priority. All activities on the ship are taking place, and our guests have been terrific at adapting to our new protocols,” Carnival said in a statement in the wake of the outbreak. The cruise line also clarified that it currently goes above and beyond CDC guidelines and requirements in its operations, adding that it now requires all passengers to wear masks in all common areas of the ship and began requiring a negative COVID test of all embarking passengers as of Aug. 14, CNN reports. RELATED: You Must Do This to Protect Yourself From Delta—Even If You’re Vaccinated.