MIAMI (REUTERS) - Royal Caribbean Group said on Wednesday (June 16) it would delay the launch of its new cruise liner by nearly a month after eight crew members tested positive for Covid-19, the latest setback in its push to restart the much-awaited US summer trips.

Odyssey of the Seas, which was scheduled to sail through the Southern and Western Caribbean from Fort Lauderdale, Florida, will now set sail on July 31 instead of July 3.

A simulation cruise, originally set for late June, will also be rescheduled.

Cruise companies have been cleared in the United States to sail under strict conditions, giving them a much needed respite after being hammered by the pandemic, although a spate of Covid-19 cases onboard are roiling their schedule.

Earlier this month, the company said two people tested positive for Covid-19 onboard Celebrity Millennium, which was among the first cruises in North America to start sailing.

On the latest cases, Royal Caribbean said six of Odyssey's eight crew members who tested positive were asymptomatic and two had mild symptoms.

The positive cases were traced following the crew's inoculation but before the effectiveness of the vaccine kicked in, the company said. All 1,400 crew members were vaccinated on June 4 and will be considered fully vaccinated on June 18, it added.

Royal Caribbean International, which has eight trips scheduled from US ports, had previously planned the voyage of its brand new ship through Israel, Greece and Cyprus but the route was later altered on security grounds.

Royal Caribbean, Carnival and Norwegian Cruise have all been cleared to set sail again after meeting regulatory guidelines, including a fully vaccinated crew.

Shares of the three companies were up more than 2 per cent each following an upgrade from Wolfe Research, which is expecting a recovery in the industry based on improved bookings and pricing trends out of North America over the past month.