Loading...
Shortly after the recognition of COVID-19, it became clear that some infected people have few or no symptoms. Quantitation of asymptomatic carriers and of their potential for transmission has been hampered by lack of ubiquitous accurate testing.
These authors report a COVID-19 outbreak on a small cruise ship en route to the Antarctic Peninsula. The passengers and crew were isolated from other persons from their departure from Ushuaia, Argentina, in mid-March 2020 until their early unscheduled docking in Montevideo, Uruguay, 13 days later. No one on board had been in countries with the most prevalent COVID-19. Before boarding, 95 crew members and 128 passengers were screened for COVID-19 symptoms and elevated temperature. Screening continued and multiple hand hygiene stations were available onboard. From the outbreak's start, passengers were strictly isolated in cabins.
On day 20, 128 (59%) of the 217 persons still onboard tested positive for COVID-19 by reverse transcription polymerase chain reaction, including some who had negative rapid-testing results. Of the 128, 19% had any COVID-19 symptoms and 81% were entirely symptom-free. Of the symptomatic patients, 8 required medical evacuation; one died. Test results were discordant among occupant pairs of 10 cabins, which the authors attribute to testing error.
Ing AJ et al. COVID-19: In the footsteps of Ernest Shackleton. Thorax 2020 May 27; [e-pub]. (https://doi.org/10.1136/thoraxjnl-2020-215091)
Comment
Despite the article's brevity, and because of the isolation and ubiquitous screening and testing of the ship's occupants, the findings provide several important lessons not so clearly assessed in larger studies. First, this is perhaps the best quantification available of the very large proportion of asymptomatic persons in a group of SARS-CoV-2–infected individuals. The findings call into question the usefulness of clinical screening as we plan to “open up” the country. The second is the inaccuracy of rapid testing modalities available early in this pandemic. The results should inform quarantine practices after disembarkation from cruise ships and return-to-work strategies.