Public health officials spent significantly more hours performing contact tracing on passengers and crew members from cruise ships than they did for flight contact investigations, USA Today reports. They performed contact tracing on 11,000 passengers and crew members from affected cruise ships.
A major issue that could have contributed to the spread of the disease post-disembarkation is the fact that not all passengers leaving ships with confirmed or possible COVID-19 outbreaks were subjected to quarantines. Some didn’t learn until after disembarking about their infections, while others were asymptomatic and unaware that the virus was spreading.
Cruise passengers tend to use multiple forms of travel before and after the actual cruise itself. Many fly to and from the port, stay at hotels and ride public transportation. This provided ample opportunity for travelers to either become infected before boarding the ship, or to spread the virus after leaving the ship.
From March 1 to July 10, the CDC counted 2,973 cases of COVID-19 or COVID-like illnesses on cruise ships. There were reportedly 99 outbreaks across 123 cruise ships. These numbers don’t include the Diamond Princess outbreak, USA Today reports.
The report also researched concerns about the spread of the virus after ships returned to port and the danger to the shoreside public.