Intended for healthcare professionals


What the Diamond Princess taught the world about covid-19

BMJ 2020; 369 doi: (Published 27 April 2020) Cite this as: BMJ 2020;369:m1632

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  1. Chris Baraniuk, freelance journalist
  1. Belfast
  1. chrisbaraniuk{at}

In the early days of the covid-19 pandemic, there was one place besides China that became infamous as a hotbed of SARS-CoV-2 transmission: a cruise ship. That ship has taught epidemiologists crucial lessons, writes Chris Baraniuk

On 20 February, the World Health Organization announced that more than half the known cases of covid-19 in the world outside China were on a single ship: the Diamond Princess.1 A 16 year old luxury vessel that cost half a billion dollars to build was stuck in quarantine in Japan with more than 3700 people on board. Hundreds of them had become sick and were confined to their cabins.

The situation was widely lamented. A Japanese epidemiologist described conditions aboard the Diamond Princess as “completely chaotic.”2 The US Centers for Disease Control and Prevention (CDC) questioned the efficacy of the onboard lockdown, and infectious disease expert Anthony Fauci, who is advising the White House on the covid-19 pandemic, said the vessel’s quarantine process had “failed.”3

But since the international spotlight moved away from the stricken cruise ship, data have been published that tell a slightly different story. It seems that the lockdown did have a measurable effect on restricting contagion. And there are signs that the ship’s ventilation and wastewater systems did not worsen the spread of …

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