The US Centers for Disease Control (CDC) has warned Americans who are at high risk of complications from COVID-19 not to go on a cruise, even if they are fully vaccinated.

The warning applies to older adults, people with weakened immune systems – including those who take medicines to suppress symptoms – and people of any age with certain underlying medical conditions.

On Friday, the CDC updated its notice ‘to recommend travellers who are at increased risk for severe illness avoid cruise ship travel, regardless of vaccination status’.

“Severe illness means that a person with COVID-19 may need: hospitalisation, intensive care, a ventilator to help them breathe or they may even die,” the updated advice on the CDC website says.

“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. Outbreaks of COVID-19 have been reported on cruise ships,” it adds.

The new warning has not changed CDC’s rating of cruise ships, which remains at level 3 ‘high’.