Cruise Ship Travel | Yellow Book

Introduction

Cruise ship travel presents a unique combination of health concerns. Travelers from diverse regions brought together in the often crowded, semi-enclosed shipboard environment can facilitate person-to-person (contact, droplet, or airborne), foodborne, and waterborne transmission of communicable diseases. Outbreaks on ships can be sustained over multiple voyages by crewmembers who remain onboard or by persistent environmental contamination. Port visits can also expose travelers to local diseases and, conversely, can be a conduit for disease introduction into shoreside communities.

For these reasons, some people (e.g., those with chronic health conditions or who are immunocompromised, older, pregnant, or very young) merit additional considerations when preparing for a cruise. Because travelers at sea might need to rely on a ship’s medical capabilities for an extended period, people with preexisting medical conditions or special needs who are considering cruise travel should prepare accordingly by contacting the cruise line’s customer service center to learn what types and level of healthcare services are (and are not) available on specific ships.

Cruise ship medical capabilities

Medical facilities on cruise ships can vary widely depending on ship size, itinerary, cruise duration, and passenger demographics. Generally, shipboard medical centers can provide medical care comparable to that of ambulatory care centers; some are capable of providing hospital-level services or renal dialysis. Although no government agency officially regulates medical practice aboard cruise ships, the American College of Emergency Physicians (ACEP) published consensus-based guidelines for cruise ship medical facilities in 1995 and updated the guidelines in 2023. ACEP guidelines, which most major cruise lines follow, state that cruise ship medical facilities should be able to provide quality medical care for passengers and crew; initiate appropriate stabilization, diagnostic, and therapeutic maneuvers for critically ill or medically unstable patients; and assist in the medical evacuation of patients in a timely fashion, when appropriate. The cost of onboard medical care—clinician exam, tests, and medications—is typically not included with a voyage’s expense. Travelers should consider purchasing insurance coverage for overseas health care, including medical evacuation. Additionally, the cost of purchasing over-the-counter medications from the ship tends to be higher. Travelers should consider packing over-the-counter medications and test kits for COVID-19 and influenza.

Illness and injury

Cruise ship medical centers treat a wide variety of illnesses and injuries, with roughly half of all passengers seeking medical care being >65 years old. Approximately 10% of all conditions reported to cruise ship medical centers are considered a medical emergency or require urgent care. About 95% of acute illnesses or injuries are treated or managed onboard, with the remainder requiring evacuation and shoreside consultation for dental, medical, or surgical issues. Any urgent ship-to-shore medical evacuations to facilities capable of providing higher levels of medical care can present logistical challenges and pose additional risks to ill patients.

Medical center visits are primarily the result of acute illness or injury. The most frequently reported diagnoses include respiratory illnesses (30%–40%); injuries from slips, trips, or falls (12%–18%); gastrointestinal (GI) illnesses (10%); and seasickness (10%). While approximately 3% of medical center visits are for cardiovascular reasons, 80% of onboard deaths are due to cardiovascular events.

Infectious disease outbreaks

The most frequently reported cruise ship outbreaks involve GI infections (e.g., norovirus), respiratory infections (e.g., COVID-19, influenza), and other vaccine-preventable diseases (VPDs), such as varicella (see COVID-19; Influenza; and Norovirus chapters). To reduce the risk of introducing communicable diseases, some ships conduct medical screening during embarkation to identify ill passengers, prevent them from boarding, or require onboard isolation if permission to board is given.

People who become ill with a communicable disease before a voyage should consult their healthcare professional and delay their travel until they are no longer contagious. When booking a cruise, travelers should check the trip cancellation policies and consider purchasing trip cancellation insurance (see Travel Insurance, Travel Health Insurance, and Medical Evacuation Insurance chapter).

Travelers who become ill during a voyage should seek care in the ship’s medical center; the onboard staff will provide clinical management, facilitate infection-control measures, and take responsibility for reporting illnesses or communicable diseases of potential public health concern.

Infectious disease health risks

Gastrointestinal illnesses

During 2006–2019, rates of GI illness among passengers on voyages lasting 3–21 days fell from 32.5 to 16.9 cases per 100,000 travel days. Despite the decrease, outbreaks have continued to occur. The Centers for Disease Control and Prevention (CDC) assists the cruise ship industry to prevent and control the introduction, transmission, and spread of GI illnesses on cruise ships. See information on cruise ship GI illnesses and updates on GI illness outbreaks involving ships with U.S. ports of call, specifically.

Norovirus

On cruise ships, >90% of GI illness outbreaks with a confirmed cause are due to norovirus. Characteristics of norovirus that facilitate outbreaks include a low infective dose, easy person-to-person transmissibility, prolonged viral shedding, absence of long-term immunity, the ability of the virus to survive routine cleaning procedures, and the absence of a vaccine (see Norovirus chapter). For international cruise ships porting in the United States during 2006–2019, an average of 12 norovirus outbreaks occurred each year.

Other sources of gastrointestinal illness

GI outbreaks on cruise ships also have been caused by contaminated food or water; most outbreaks were associated with Campylobacter, Clostridium perfringens, or enterotoxigenic Escherichia coli.

Protective measures

Travelers can reduce the risk of acquiring a GI illness on cruise ships by frequently washing hands with soap and water, especially before eating and after using the restroom. Because of the elevated risk of outbreaks in the cruise ship environment, travelers should call the ship’s medical center promptly, even for mild symptoms of a GI illness, and strictly follow cruise ship guidance regarding isolation and other infection-control measures.

Respiratory illnesses

Respiratory illnesses are the most common medical complaint on cruise ships. During the pre-travel visit, evaluate whether vaccines or boosters (e.g., COVID-19, influenza) are needed and emphasize the importance of practicing good respiratory hygiene and cough etiquette while onboard (see The Pre-Travel Consultation and Vaccination and Immunoprophylaxis—General Principles chapters). As with GI illnesses, cruise ship passengers should report respiratory illness to the medical center promptly and follow isolation recommendations as instructed. CDC has developed guidance designed to help cruise ship operators provide a safer and healthier environment for crewmembers, passengers, port personnel, and communities.

Coronavirus disease 2019

SARS-CoV-2, the virus that causes COVID-19, spreads more easily between people in close quarters, and multiple studies have concluded that transmission rates of SARS-CoV-2 among travelers on ships are much greater than in other settings (see COVID-19 chapter). Cruise ship COVID-19 outbreaks can overwhelm onboard medical and public health resources.

Cruise passengers and crewmembers who are not up to date with their COVID-19 vaccines are at increased risk for severe illness, hospitalization, medical evacuation, and death. Since cruising will always pose some risk of SARS-CoV-2 transmission, ensure that people planning cruise ship travel are up to date with their vaccinations and assess their likelihood for developing severe COVID-19. For people at increased risk of severe COVID-19, regardless of their vaccination status (e.g., people who are ≥65 years of age, pregnant, or immunocompromised), discuss their eligibility for antivirals and the potential health hazards associated with cruise ship travel.

Influenza

Historically, influenza has been among the most often reported VPDs occurring on cruise ships. Because passengers and crew originate from all regions of the globe, shipboard outbreaks of influenza A and B can occur year-round, with exposure to strains circulating in different parts of the world (see Influenza chapter). If vaccine is available and no contraindication exists, anyone planning a cruise who has not received the current seasonal influenza vaccine should be vaccinated ≥2 weeks before travel. For people at high risk for influenza complications, healthcare professionals should discuss the need for antiviral chemoprophylaxis and/or treatment and the importance of presenting to the ship medical center when either are indicated.

Respiratory syncytial virus infection

Similar to COVID-19 and influenza, outbreaks of respiratory syncytial virus (RSV) can occur at any time of the year among cruise ship passengers and crew members. RSV vaccines have been approved for certain higher-risk populations, including older adults and pregnant women. Prior to cruise travel, healthcare professionals should discuss these preventive options with eligible travelers.

Legionnaires’ disease

While less common on cruise ships, Legionnaires’ disease is nevertheless a treatable bacterial infection that can result in severe pneumonia leading to death. Approximately 10% of Legionnaires’ disease cases reported to CDC during 2015–2016 occurred in people who traveled during the 10 days before symptom onset. Clusters of Legionnaires’ disease associated with hotel or cruise ship travel can be difficult to detect because travelers often disperse from the source of infection before symptoms begin. Data reported to CDC during 2015–2016 included 35 confirmed cases of Legionnaires’ disease associated with cruise ship exposures.

In general, Legionnaires’ disease is contracted by inhaling warm, aerosolized water containing the bacteria Legionella. Transmission can also occur through aspiration of Legionella-containing water. Typically, people do not spread Legionella to others; a single episode of possible person-to-person transmission of Legionnaires’ disease has been reported. Contaminated hot tubs are commonly implicated as a source of shipboard Legionella outbreaks, although potable water supply systems also have been culpable. Improvements in ship design and standardization of water disinfection have reduced the risk for Legionella growth and colonization.

People with suspected Legionnaires’ disease require prompt antibiotic treatment. When evaluating cruise travelers for Legionnaires’ disease, obtain a thorough travel history of all destinations during the 10 days before symptom onset to assist in identifying potential sources of exposure and collect urine for Legionella antigen testing, which detects L. pneumophila serogroup 1, the most common serogroup. Most cruise ships also have the capacity to perform this test. Healthcare professionals and health departments should also notify CDC of any travel-associated Legionnaires’ disease cases by sending an email to [email protected].

Other vaccine-preventable diseases

Although most cruise ship passengers come from countries with routine vaccination programs (e.g., Canada, the United States), many of the crew are from low- or middle-income countries where immunization rates can be low. Outbreaks of hepatitis A, measles, meningococcal disease, mumps, pertussis, rubella, and varicella have all been reported on cruise ships. The majority (82%) of these outbreaks occur among crew members; prior to the COVID-19 pandemic, varicella was the most frequently reported VPD. Other VPDs (e.g., pertussis) occur more often among passengers.

Each cruise line sets its own policies regarding vaccinations for its crew; some have limited or no requirements. Thus, all passengers should be up to date with routine vaccinations before travel, as well as any required or recommended vaccinations specific for their destinations (see Vaccination and Immunoprophylaxis—General Principles chapter). Women of childbearing potential should have documented immunity to measles, rubella, and varicella (either by vaccination or titer) before cruise ship travel.

Vector-borne diseases

Some cruise ship ports of call include destinations where vector-borne diseases (e.g., dengue, Japanese encephalitis, malaria, yellow fever, Zika) are known to be endemic. In addition, new diseases can surface in unexpected locations; chikungunya was reported for the first time in the Caribbean in late 2013, with subsequent spread throughout the region and numerous other North, Central, and South American countries and territories. Zika was first reported in Brazil in 2015 and subsequently spread across the Caribbean and Latin America, sparking concern because of its association with microcephaly and other congenital abnormalities in the fetus. For disease-specific information, see the relevant chapters of Section 4.

For guidance on how to avoid bites from mosquitoes and other disease-transmitting arthropod vectors, both onboard and while on shore at ports of call, see the Mosquitoes, Ticks, and Other Arthropods chapter. For specific details on yellow fever vaccination and malaria prevention, see the Yellow Fever Vaccine and Malaria Prevention Information, by Country chapter.

Noninfectious health risks

Stresses of cruise ship travel include varying weather and environmental conditions, and unaccustomed changes to diet and levels of physical activity. Despite modern stabilizer systems, seasickness is a common complaint, affecting up to 25% of travelers (see Motion Sickness chapter). Note that travel is an independent risk factor for behaviors such as alcohol and illicit drug use and misuse, and unsafe sex (see Substance Use and Substance Use Disorders in Travelers and Sex and Travel chapter).

Travel preparation

Cruise ship travelers often have complex itineraries due to multiple short port visits. Although most port visits do not include overnight stays off ship, some trips offer travelers the opportunity to venture off the ship for ≥1 night. These excursions can complicate decisions about exposures and the need for specific antimicrobial prophylaxis, immunizations, and other prevention measures. Box 7.5.1 and Box 7.5.2 summarize recommended cruise travel preparations and healthy behaviors during travel for healthcare professionals and cruise ship travelers.

Travelers with additional considerations

Travelers with chronic illnesses and travelers with disabilities who have additional needs (e.g., dialysis, supplemental oxygen, wheelchairs) should inform their cruise line before traveling to ensure the ship can support their needs (see Travelers with Chronic Illnesses and Travelers with Disabilities chapters). Severely allergic travelers and travelers with underlying medical conditions should carry a hard or digital file that contains essential, pertinent health information (e.g., allergies, blood type, chest radiograph [if abnormal], chronic conditions, electrocardiogram, medication list, primary healthcare professional and specialist contact information; see Severely Allergic Travelers chapter). Travelers also should bring any medications prescribed or recommended by their healthcare professional (e.g., an epinephrine auto-injector) to help facilitate care during a medical emergency. For detailed information on preparing travelers who have additional considerations for international travel, including severe allergies, chronic illness, disabilities, or immune compromise, see Section 2.

Pregnant travelers

Most cruise lines have policies that do not permit women to board after their 24th week of pregnancy. Contact cruise lines directly for specific guidance before booking. For additional information on preparing pregnant women for international travel, see the Pregnant Travelers chapter.

Insurance coverage

All prospective cruise travelers should verify coverage with their health insurance carriers and, if not included, consider purchasing additional insurance to cover medical evacuation and health services received onboard cruise ships and in foreign countries (see Travel Insurance, Travel Health Insurance, and Medical Evacuation Insurance chapter).

Box 7.5.1

Box 7.5.2

Cruise ship illness and death reporting and public health interventions

Federal regulations mandate that before arrival, the person in charge of a conveyance destined for a U.S. port of entry must report to the CDC port health station of jurisdiction any death or “ill person” among passengers or crew. For information about this requirement, see CFR Title 42 §71.21: Report of death or illness. CDC provides guidance to cruise lines on reporting ill travelers and deaths on board at Maritime Guidance: Reporting Death or Illness on Ships.

Most reports of illness or death on cruise ships are received directly from the ship’s medical staff. Notifications to CDC of illnesses or deaths among cruise travelers also can originate from other federal partners or state, tribal, local, or territorial health departments, particularly when the illness or death is identified after cruise ship disembarkation. Healthcare professionals should contact their local health department if they identify a traveler with a communicable disease of public health concern following cruise travel.

Illnesses

For public health responses to ill cruise ship passengers and crew, control measures typically are initiated while the ship is still at sea. CDC port health station personnel obtain clinical and epidemiologic information about the ill or deceased person(s), determine public health risk, and provide guidance to the ship’s healthcare professionals about case findings, infection control measures, and contact investigations.

CDC port health station personnel might respond by meeting a ship at the port of entry to further investigate or to assist the responding health department with surveillance and control measures. CDC personnel also might provide onsite response for outbreaks or clusters of disease, quarantinable communicable diseases, and some vaccine-preventable diseases (e.g., measles, rubella). CDC’s Vessel Sanitation Program is responsible for responding to reports of acute gastroenteritis on cruise ships. CDC’s Legionella Team is responsible for responding to reports of legionellosis.

CDC provides guidance to cruise lines on managing ill travelers at Cruise Ship Guidance: Disease-Specific Management of Ill Passengers/Crew.

Deaths

The intent of the regulatory requirement for reporting deaths is for CDC to determine if any of these deaths were due to a communicable disease of public health concern. Morgues exist on board that can manage the remains of travelers who die during a cruise voyage, and healthcare professionals can perform some post-mortem testing for communicable diseases (e.g., COVID-19 or influenza testing on respiratory specimens).