SYDNEY – The spread of Covid-19 on cruise ships may have been “significantly underestimated” and asymptomatic cases may be many more than expected. To raise the question is the case of a cruise ship, which left Argentina for Antarctica in March, where there were more than 8 out of 10 people without symptoms among those who tested positive. A study by Macquarie University Hospital in Sydney explains this in Thorax magazine.
The researchers led by Alvin Ing, all on board, describe what happened on the ship with 128 passengers and 95 crew members, who left Ushuaia for a 21-day cruise in mid-March.
All precautions were taken: passengers who had traveled through countries with already high rates of Covid-19 infection in the previous three weeks were not allowed to board. Everyone’s temperature was measured on boarding, and there were many points for hand hygiene on board, especially in the restaurant.
The first case of fever emerged on the eighth day, immediately triggering the control measures (confinement in the passenger cabin, stop to daily maintenance apart from the delivery of meals, protective devices to staff in contact with sick passengers).
When Argentina closed its borders, the ship headed to Montevideo in Uruguay, arriving there on the thirteenth day. A time when hospitalization was requested for eight people – including passengers and crew. On the twentieth day the 217 people left (including passengers and crew) took the swab, proving positive in over half of the cases (128, equal to 59%). Of these, 19% (24) had symptoms, while 81% (108) did not. The ship had no contact with other people for 28 days after departure, remaining virtually isolated.
According to the researchers, the prevalence of the infection on cruise ships was probably “significantly underestimated”, and passengers after disembarkation should be monitored to avoid further contagion.