Maritime varicella illness and death reporting, U.S., 2010–2015

Background: Ships destined for, or departing from, U.S. ports of entry must report certain signs and symptoms of potentially communicable diseases of public health interest among travelers to the Division of Global Migration and Quarantine (DGMQ) at the Centers for Disease Control and Prevention. Methods: We reviewed ships’ varicella case and outbreak reports from January 2010 through December 2015. Results: DGMQ received 967 reports of varicella and 13 reports of herpes zoster. Most varicella case-patients were 20–49 years of age (84.7%, 472/557) and were cruise ship crew members (78.4%, 758/967). Most often, cruise ship crew member case-patients were born in or held passports from Indonesia (21.7%, 80/369), Philippines (17.6%, 65/369), or India (17.3%, 64/369). Ninety-nine varicella outbreaks were reported, including 439 varicella cases and one herpes zoster case; 97 (98.0%) outbreaks occurred on cruise ships, and 90.2% of associated cases were among crew members (397/440). Most varicella cases were in crew members, who are adults often from tropical regions where varicella immunity is acquired later in childhood or young adulthood or without varicella vaccination programs. Conclusion: Varicella vaccination as appropriate for susceptible travelers, particularly crew members, before maritime travel may decrease risk of varicella infection and prevent outbreaks on ships.