The confined environment of a ship promotes the transmission of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) due to close contact among the population on board. The study aims to provide an overview of outbreaks of SARS-CoV-2 on board of cruise, navy or cargo ships, to identify relevant outbreak management techniques, related problems and to derive recommendations for prevention. Four databases were searched. The study selection included reports about seroprevalences or clinically/laboratory confirmed infections of SARS-CoV-2 on board ships between the first of January, 2020 and the end of July, 2020. A total of 37 studies were included of whom 33 reported outbreaks of SARS-CoV-2 on cruise ships (27 studies referred to the Diamond Princess). Two studies considered outbreaks on the Grand Princess, three studies informed about Nile River cruises and one study about the MS Westerdam (mention of multiple outbreaks possible in one study). Additionally, three studies reported outbreaks of SARS-CoV-2 on navy vessels and one study referred to a cargo ship. Problems in handling outbreaks resulted from a high number of asymptomatic infections, transportation issues, challenges in communication or limited access to health care. Responsible operators need to implement infection control measures which should be described in outbreak management plans for ships to prevent transmission risks, including, e.g., education, testing strategies, communication lines, social distancing and hygiene regulations.

Within the framework of the interdisciplinary research project ARMIHN (Adaptive Resilience Management in the Port) a two-day large-scale exercise took place in the Port of Hamburg in October 2021. Due to the COVID-19 pandemic, the exercise could not be realized as a full-scale exercise with a large number of participants and actors as originally planned. Therefore, a hybrid exercise concept with virtual and live parts was developed. The project ARMIHN has shown that the planning, organization, and implementation of a hybrid large-scale exercise is demanding, resource- and time-intensive. On the other hand, the project showed the possibility for exercises to be conducted even when underlying conditions like the COVID-19 pandemic do not support a full-scale exercise in presence.