Introduction:
Infectious diseases might pose a significant risk to public health in maritime settings, particularly on large passenger ships, where close contact and shared spaces heighten the potential for outbreaks, if control measures are not in place. Task 3.7.2, a part of the EU Healthy Sailing initiative, aims to develop evidence-based vaccination guidelines to prevent vaccine preventable diseases.

Methods:
A comprehensive review of existing ship operational frameworks good practices, literature and guidelines from organizations including WHO, IMO, ECDC, and EMSA was conducted. A questionnaire was sent to four cruise lines and one ferry line to gather information on current vaccination practices. The extracted data was categorized as follows: 1) Vaccine recommendations from WHO for travelers and occupational groups relevant to passenger ships 2) Vaccine recommendations for crew and passengers 3) Timing of the vaccination: a) as a condition of employment (for crew) b) before travelling at any destination (for passengers) c) before travelling at certain destination (for passengers and crew) d) as part of outbreak management 4) Prioritization scale 1-5 Expert opinions and input from target groups, including the cruise and ferry industries, have been gathered to ensure the guidelines' relevance and practicality. The task drew on outcomes from related Healthy Sailing tasks and lessons learned from previous outbreaks like COVID-19.

Results:
Two of the five companies have shared guidelines, and data collection is ongoing. Vaccination strategies were categorized by ship and voyage type. The working group is developing a list of vaccine-preventable diseases for potential inclusion, with special focus on crew and passengers traveling to endemic regions, recommendations will be tailored to specific crew departments and positions.

Conclusions:
The developed guidelines will offer an evidence-based framework for vaccination on large passenger ships, aligning with international standards to enhance maritime health safety. Pilot testing on operational vessels will assess their practicality, with feedback from operators and authorities incorporated into the final version.