Mem Inst Oswaldo Cruz, Rio de Janeiro, VOLUME 117 | 2022
Research Articles

COVID-19 outbreaks among crew members in non-cruise vessels anchoring in Salvador, Brazil, 2021

Cristiane Wanderley Cardoso1,2,+, Mirela Maisa da Silva Souza1, Ana Claudia Venegeroles de Sá Teles3, Hernan Dario Argibay2, Olivete Borba dos Reis1, Felicidade Mota Pereira4, Marta Giovanetti5, Tereza Magalhaes6,7, Guilherme Sousa Ribeiro2,6

1Secretaria Municipal de Saúde de Salvador, Salvador, BA, Brasil
2Fundação Oswaldo Cruz-Fiocruz, Instituto Gonçalo Moniz, Salvador, BA, Brasil
3Agência Nacional de Vigilância Sanitária, Salvador, BA, Brasil
4Secretaria de Saúde do Estado da Bahia, Salvador, BA, Brasil
5Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Flavivírus, Rio de Janeiro, RJ, Brasil
6Universidade Federal da Bahia, Faculdade de Medicina, Salvador, BA, Brasil
7Colorado State University, Center for Vector-Borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Fort Collins, CO, USA

DOI: 10.1590/0074-02760220114
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BACKGROUND The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected the maritime sector due to virus transmission onboard and traffic restrictions. However, reports of SARS-CoV-2 transmission on board have been mostly restricted to those occurring on cruise ships.
OBJECTIVES To report COVID-19 outbreaks in eight non-cruise vessels and discuss measures to prevent and control the onboard transmission of SARS-CoV-2.
METHODS We investigated outbreaks of COVID-19 on vessels anchoring in Baía de Todos-os-Santos, Salvador, Brazil, between February and November 2021.
FINDINGS Most vessels were cargo ships that had docked several times before anchoring in Salvador (five had docked in ≥ 9 ports). The crew ranged from 22 to 63 members. The infection attack rate on each vessel ranged from 9.7 to 88.9%. The risk of symptomatic infection largely varied among the crew of each vessel (0 to 91.6%). Overall, the risk of developing COVID-19 signs and symptoms was lower among crew members vaccinated (age-adjusted risk ratio: 0.19; 95% confidence interval 0.06-0.65). SARS-CoV-2 variants not previously identified in Salvador were detected (C.14, B.1.617.2 and B.1.351).
MAIN CONCLUSIONS Despite maritime guidelines to avert COVID-19 on board, outbreaks have happened. The multiple stopovers of non-cruise vessels during their routes may contribute to the spread of SARS-CoV-2 variants worldwide. Reducing the onboard transmission of SARS-CoV-2 depends on joint efforts by the crew and local health authorities and, equally important, achieving high vaccination coverage to prevent infections and illness.

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Financial support: CIEVS, SMS Salvador, Fiocruz, UFBA.
GSR received research scholarships (307450/2017-1; 311365/2021-3) from the CNPq.
+ Corresponding author:
Received 15 May 2022
Accepted 10 October 2022

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