COVID-19: Transmission amongst cruise ship passengers

COVID-19: Transmission amongst cruise ship passengers. Jefferson T, Heneghan C.

Published on June 17, 2020

Reference Ing AJ, Cocks C, Green JP. COVID-19: in the footsteps of Ernest Shackleton. 2020
Study type
Country South Atlantic
Setting Cruise ship
Funding Details None declared
Transmission mode Close contact, Person to person, Fomite
Exposures Cruise Ship

Bottom Line

Eighty-one percent of COVID 19 patients on a cruise ship were asymptomatic. Prevalence on affected cruise ships is likely to be underestimated and monitoring after disembarkation is necessary.

Evidence Summary

The prevalence of COVID-19 on affected cruise ships is likely to be significantly underestimated, and strategies are needed to assess and monitor all passengers to prevent community transmission after disembarkation. The presence of discordant COVID-19 results in numerous cabins suggests that there may be a significant false-negative rate with RT- PCR testing. Follow- up testing is being performed to determine this.

  • Rapid Antibody testing of patients in the acute phase is unreliable.
  • The majority of COVID-19- positive patients were asymptomatic (81%).
  • The timing of symptoms in some passengers (day 24) suggests that there may have been cross-contamination after cabin isolation.

What did they do?

The 128 passengers and 95 crew were screened for COVID-19 symptoms (including body temperature) before boarding. Passengers from South East Asia were not allowed aboard.

On day 8 of the cruise (which had been aborted because of international border controls) the first case appeared and was immediately isolated. Barriers were used throughout the ship. Other cases followed among passengers and crew. On day 17 a seriously ill patient was admitted to hospital in Montevideo followed by 7 others in the following days.

All 217 passengers and crew were tested on day 20, and 128 (59%) tested positive for COVID-19. In ten cases two passengers sharing a cabin recorded positive and negative result, that is 20/128 (16%).

Study reliability

All passengers were tested. The main limitation will be the accuracy of the tests. The Antibody test used was the ivaDiag qSARS-CoV-IgM/IgG Rapid Test.  On board SARS-CoV-2 virus testing occurred on 3 April (day 20; ATGen-Diagnostica, Montevideo) with CDC 2019-nCoV Real-Time RT-PCR Diagnostic Panel.

Clearly defined setting Demographic characteristics described Follow-up length was sufficient Transmission outcomes assessed Main biases are taken into consideration
Yes No Yes Yes No

About the authors

Carl Heneghan

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

Tom Jefferson, epidemiologist.