An unusual cruise offers insight on how common it is for people to have a silent infection with COVID-19. The cruise was an expedition to Antarctica that intended to follow in the footsteps of Ernest Shackleton. All of those who boarded in Argentina for their mid-March departure were screened before embarking. Shortly after the ship left port, the World Health Organization declared a global pandemic.
Silent Infection With COVID-19:
There were 217 people on board, including crew. Because the boat was not allowed to dock anywhere for two weeks, it acted as a sealed bubble. Despite careful infection control procedures, people began to become ill. Two weeks after departure, the ship arrived in Montevideo, Uruguay. Eventually, eight passengers and crew needed medical evacuation for hospitalization. Three required intubation; one died (Thorax, May 27, 2020).
Everyone else on board was tested for COVID-19 infection. Nearly 60 percent tested positive. However, eight out of ten of those individuals did not have symptoms. Instead, they had a silent infection with COVID-19.
In several instances, two people sharing a cabin had different test results, with one testing positive and the other testing negative. The researchers (who were part of the expedition) suggest that this might be due to a high false negative rate of the tests. They recommend that people receiving a negative test result be retested some time later to confirm the result.
Testing Everyone Who Gets Off a Ship:
In addition, they stress the importance of monitoring the health of anyone getting off a cruise ship to reduce the potential for community spread of the virus. After all, if such a high proportion of people carry the virus, they could easily spread it far and wide. This is especially true for those with a silent infection with COVID-19. Without symptoms, they may not realize that they should be exercising particular care to keep from sharing infectious viral particles with susceptible individuals.
People who like to listen may find the BMJ podcast informative. Here is the link.
