COVID-19: Transmission aboard the Diamond Princess cruise ship
COVID-19: Transmission aboard the Diamond Princess cruise ship. Jefferson T, Heneghan C.
Published on June 18, 2020
Transmission Dynamics of COVID-19
||Kakimoto K, Kamiya H, Yamagishi T, Matsui T, Suzuki M, Wakita T Investigation of Transmission of COVID-19 Among Crew Members During Quarantine of a Cruise Ship — Yokohama, Japan MMWR Morb Mortal Wkly Rep 2020;69:312-313.
||International waters and Yokohama, Japan
||MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services.
||Close contact, Person to person, Fomite
||Cruise Ship, passenger turnover
Swift action by diagnosis, testing, contact-tracing and isolation would have probably avoided the majority of 619 cases aboard.
Two cases in passengers infected other passengers and ultimately some service crew members (6% of the crew) who served food in their cabins. As these messed with other crewmembers, they infected some and those whose accommodation deck they shared.
The crew dining area was the primary area of congregation; passengers did not access this part of the ship.
- 15/20 confirmed cases in crew members occurred among food service workers
- 16/20 cases occurred among those with cabins on deck 3, the deck on which the food service workers lived
Delay in diagnosing, contact tracing and isolation probably facilitated transmission which the authors hypothesise as being by contact and droplet.
What did they do?
There are two papers on the Diamond Princess outbreak. The first by Kakimoto is a preliminary report of the investigation carried out onboard the cruise ship Diamond Princess when docked at Yokohama, Japan. The second is a model estimating IFRs, with inference from the epidemiological characteristics of the ship outbreak to the population of China (not discussed)
Japanese public health officials investigated the ship outbreak with a combination of enquiry, testing and follow-up.
The preliminary report is unclear as to the actual potential contact between food service crew members and quarantined passengers. Followup of passengers and crew beyond the end of February is unclear.
|Clearly defined setting
||Demographic characteristics described
||Follow-up length was sufficient
||Transmission outcomes assessed
||Main biases are taken into consideration
What else should I consider?
The research hypothesises that in closed or crowded areas where a large number of individuals gather requires swift action if there is an outbreak.
Asymptomatic COVID-19 cases on the Diamond Princess cruise ship
COVID-19: Transmission of the novel coronavirus onboard the Diamond Princess Cruises Ship
About the authors
Carl is Professor of EBM & Director of CEBM at the University of Oxford. He is also a GP and tweets @carlheneghan. He has an active interest in discovering the truth behind health research findings
Tom Jefferson, epidemiologist.