Measles, rubella, and varicella among the crew of a cruise ship sailing from Florida, United States, 2006.

Background: Cruise ship outbreaks of vaccine-preventable diseases (VPD) such as rubella and varicella have been previously associated with introduction and spread among susceptible crew members originating from countries with endemic transmission of these diseases.

Methods: During February to April 2006, we investigated a cluster of rash illnesses due to measles, rubella, or varicella on a cruise ship sailing from Florida to the Caribbean. Case-finding measures included review of medical logs, active surveillance for rash illness among crew members, and passive surveillance for rash illness in the ship's infirmary lasting two incubation periods from the last case of measles. Passengers with potential exposure to these VPD were notified by letters. All susceptible crew members with potential exposure were administered the measles, mumps, and rubella vaccine after informed consent.

Results: A total of 16 cases were identified only among crew members: 1 rubella, 3 measles (two-generation spread), 11 varicella (three-generation spread), and 1 unknown diagnosis. Of 1,197 crew members evaluated, 4 had proof of immunity to measles and rubella. Based on passive surveillance, no cases were identified among passengers, the majority of whom resided in the United States.

Conclusion: The international makeup of the population aboard cruise ships combined with their semi-enclosed environment has the potential to facilitate introduction and spread of VPD such as measles, rubella, and varicella onboard and into communities. Cruise lines should ensure crew members have evidence of immunity to these diseases. Passengers should be up to date with all vaccinations, including those that are travel-specific, prior to embarking on cruise travel.