Recommendations for Cruise Lines to Help Reduce Risk of Measles Transmission

Recommendations for Measles Prevention

For information on measles signs and symptoms, incubation period, and complications, visit www.cdc.gov/measles.

Measles education and awareness

Among Crew

Educating crew members about the following items may help reduce the risk of measles transmission on board

• Risk of measles during international travel
• Signs and symptoms that may indicate a sick traveler has measles
• Strategies the ship's medical staff can take to reduce the risk of onboard measles transmission
• Requirement for the cruise ship's medical staff to report any ill traveler that meets the regulatory definition of "ill person"
  • Request for the cruise ship's medical staff to report any traveler who is suspected or confirmed of having measles, even if they do not meet the "ill person" definition
• Vaccination recommendations
  • Recommend employees who do not have presumptive evidence of immunity to be fully vaccinated against measles
  • For international travel, people are considered fully vaccinated when they have a written record of receiving two doses of measles-containing vaccine at least 28 days apart completed at least two weeks prior to departure
• Importance of self-isolating on a ship while sick with fever, especially if they also have a rash or are coughing.
  • Crew members who develop these symptoms should not report to work. Instead, they should remain in their cabins (or placed in a solo crew cabin if available to isolate them from any roommates) and notify their supervisors and the ship's medical center.

Among Passengers

Encouraging passengers to consider the following actions may help reduce the risk of measles transmission on board

• Be fully vaccinated against measles before travel or have presumptive evidence of immunity. Delay travel if they are sick with fever and a rash. Passengers who have a measles diagnosis should not travel until a doctor or public health official clears them for travel.

Vaccination Recommendations for International Travelers

CDC recommends that all people planning international travel, including cruise ship crew, be fully vaccinated against measles. Infant travelers 6 through 11 months old should receive 1 dose of MMR vaccine before international travel and should subsequently get 2 more doses at least 28 days apart after their first birthday.

The MMR (measles-mumps-rubella) and MMRV (measles-mumps-rubella-varicella) vaccines are very safe and effective. Two doses of measles-containing vaccine are about 97% effective at preventing measles; one dose is about 93% effective.

Being fully vaccinated against measles is especially important for international travelers—including cruise ship crew, contractors, and corporate staff visiting or traveling on cruise ships. That's because measles is still common in many parts of the world.

Measles vaccine should not be administered to people who previously experienced a severe allergic reaction to the vaccine or a vaccine component, have a known immunocompromising condition, or are pregnant.

Immunity to measles among crew

Cruise lines can help protect their crew from measles by:

• Confirming their employees are protected against measles through vaccination or other presumptive evidence of immunity.
• Maintaining documentation of measles vaccination or other evidence of immunity for all employees.
• To the extent possible, minimizing barriers to crew vaccination, for example, by ensuring adequate stock of MMR in ships' medical centers and by offering MMR vaccines to employees.

Understanding their own medical history, MMR vaccination status, the risk of measles exposure, and the potential risks of measles infection can help crew members make informed decisions regarding vaccination and other preventative measures based on their measles immunity status.

Presumptive evidence of immunity to measles

Presumptive evidence of immunity to measles includes at least one of the following:

• Written documentation of adequate vaccination:
  • 1 or more doses of a measles-containing vaccine administered on or after the first birthday for preschool-age children and adults not at high risk
  • 2 doses of measles-containing vaccine for school-age children and adults at high risk, which includes college students, healthcare personnel, and international travelers
• Laboratory evidence of immunity
• Laboratory confirmation of measles
• Birth in the United States before 1957

Cruise lines can help sick travelers delay travel

People should delay travel if they have a fever, especially if they also have a rash or are coughing. People who have a measles diagnosis should not travel until a doctor or public health official clears them for travel to reduce risk of measles transmission. Public health officials may also ask travelers who were exposed to measles and are not immune to delay travel until they are no longer at risk of becoming infectious. Travelers who have a fever and other signs or symptoms of measles, or are suspected or confirmed to have measles, may be more willing to delay travel for public health reasons if cruise lines allow passengers to modify their itineraries without penalties if due to illness.

Managing travelers with known or suspected measles

Actions to control transmission of possible measles on the ship need to start before laboratory results are known. People with measles are considered to be infectious from 4 days before through 4 days after their rash appears. Isolating people as soon as measles is suspected is critical to prevent spreading.

The following are best practices for people on board with signs or symptoms of measles to reduce the risk of spreading the virus to others:

• Self-isolating in their cabins with the door closed.
• Calling the ship's medical center and arranging for medical evaluation, possibly in their cabins to avoid exposing others.

Crew members with signs or symptoms of measles should notify their supervisor and report their illness to the ship's medical center, according to shipboard protocols. Sick crew members suspected of having measles should remain isolated in their cabins with the door closed or the ship's medical center in designated single-patient isolation rooms, as ordered by medical center staff according to shipboard protocols.

An isolation room with negative air pressure capacity (also known as an airborne infection isolation room) is preferred for any person with known or suspected measles. If that is not available, a cabin without other occupants can be used—rooms that do not share air with other occupied cabins to the extent possible and with the door closed. Place a face mask on the patient if tolerated, particularly when not in an isolation room or when being moved. If a face mask is not available or cannot be tolerated, ask the sick person to cover their mouth and nose with tissues when coughing. Children younger than 2 years should not wear masks because of the risk of suffocation. After the person leaves the room, it should remain vacant for at least two hours, because measles can remain infectious in the air for up to two hours.

Isolate crew members and passengers while infectious (that is, until completion of 4 days after the beginning of the rash, with rash onset as Day 0). On Day 5, no movement restrictions are necessary.

Minimize other passengers' and crew's contact with the sick person. While infectious, to the extent possible, the sick person should have no contact with any infants or people who may have a weakened immune system, or pregnant women without known immunity to measles. If possible, designate one crew member with presumptive evidence of immunity to measles to serve the sick person.

Regardless of immune status, all ship medical staff should use respiratory protection (at least as protective as a NIOSH Approved® N95® respirator^B) and standard precautions when caring for sick travelers suspected of having measles, including when entering the patient's isolation room.

CDC provides additional guidance on preventing and controlling measles in healthcare settings.

The Occupational Safety and Health Administration provides additional information on the control and prevention of measles in the workplace.

There is no specific antiviral therapy for measles. Immunoglobulin is not indicated for the treatment of patients with suspected or confirmed measles. Supportive medical care helps relieve symptoms and address complications.

Diagnostic laboratory testing needed

CDC recommends laboratory testing for all suspected measles cases. Upon receiving a report from the ship's medical staff of suspect measles in a passenger or crew member, the CDC port health station with jurisdiction for the next U.S. port of entry will inquire if measles virus testing is feasible in the vicinity of the port. If testing is feasible, the port health station will work with the ship, state or local health department, and other health partners to ensure proper specimen collection and transport to the testing laboratory. If necessary, arrangements may be made for testing in another location.

Detecting measles-specific IgM antibody in serum and measles RNA by real-time polymerase chain reaction (RT-PCR) in respiratory specimens (throat or nasopharyngeal swab samples) are the most common methods for confirming measles infection. Urine samples may also contain virus (detectable by RT-PCR). When feasible to do so, collecting both respiratory and urine samples, in addition to serum, can increase the likelihood of detecting measles virus.

Case definitions for measles are available online.

Managing sick travelers upon disembarkation

Based on application of general infection control and prevention guidance, cruise lines can organize disembarkation so that infectious travelers disembark the ship last, unless they are critically ill, to reduce possibility of exposing others. The sick person should wear a face mask, if tolerated, during disembarkation. For those patients requiring transfer to a hospital, the cruise ship should notify emergency medical services and the admitting medical facility before arrival and arrange for medical transportation to the facility with infection control precautions in place. The CDC port health station will notify port partners and the local health department that a traveler with suspected or confirmed measles will disembark to help coordinate transportation to a medical facility or to any other location such as a private home or hotel. Cruise ships should notify the CDC port health station of any person with suspected or confirmed measles who intends to travel by commercial airline or other public means after disembarkation.

Managing travelers after possible exposure

For suspected or confirmed measles cases, the CDC port health station of jurisdiction can provide specific recommendations about identifying contacts, assessing for measles immunity, providing post-exposure prophylaxis to susceptible contacts, and performing surveillance for additional cases. Cruise ships should notify the CDC port health station of any susceptible contacts who intend to travel by commercial airline or other public means after disembarkation.

Vaccine and immune globulin as post-exposure prophylaxis

Post-exposure prophylaxis (PEP) with MMR vaccine administered within 72 hours of initial exposure, or immune globulin (IG) within 6 days of exposure, may provide protection or modify the clinical course of disease among susceptible exposed contacts. The decision to administer vaccine or IG depends on several factors. These factors include the degree of clinical suspicion for measles in the source patient (or availability of laboratory confirmation), risk factors for more severe disease in exposed and susceptible people, epidemiologic information about the intensity and duration of the exposure, contraindications to vaccination among exposed people, and the ship's vaccine and IG supplies.

IG is recommended for people at risk of severe illness and complications from measles or when the MMR vaccine is contraindicated. This includes infants younger than 12 months, pregnant women without evidence of measles immunity, and people with immunocompromising conditions. For infants aged 6 through 11 months, MMR vaccine can be given in place of IG, if administered within 72 hours of exposure. Do not administer MMR vaccine and IG simultaneously, as this practice invalidates the vaccine. CDC has posted more detailed guidance about PEP for measles.

People who receive PEP and remain on board should be monitored by cruise ship medical staff for signs and symptoms consistent with measles. People who received MMR should be monitored for 1 incubation period (21 days), and people who received IG should be monitored for 28 days (due to possible prolongation of the incubation period), after the last possible exposure.

Exclusion of nonimmune exposed crew

Cruise ships may want to consider excluding exposed crew members who are not healthcare personnel from working near passengers or other crew members if the exposed crew member

• has no presumptive evidence of measles immunity, and
• did not receive PEP (vaccine or IG) during the recommended time frames.

Exclusion is recommended starting on Day 5 after the first possible exposure through Day 21 (or day 28 if IG received) after the last possible exposure.

Cruise ships should exclude shipboard healthcare personnel without evidence of immunity from duty from Day 5 after first exposure to Day 21 (or day 28 if IG received) after last exposure, regardless of PEP.

Reporting suspected cases of measles

The U.S. Code of Federal Regulations (CFR) Title 42, Part 71 requires ship captains to report all deaths and certain illnesses to the CDC port health station at or nearest the next U.S. port of arrival. Report deaths and certain illnesses—including fever and rash—before arrival at the next port or as soon as recognized.

The Maritime Conveyance Illness or Death Investigation Form is the preferred method of reporting suspect cases of measles to CDC. Ships may submit this form by email, fax, or phone. See instructions on CDC's webpage: Reporting Death or Illness on Ships.

CDC assistance

CDC can help cruise lines in their response to measles cases or an outbreak aboard a ship. CDC can:

• Notify port partners (e.g., U.S. Coast Guard, port directors) before or after arrival
• Provide guidance and assistance with coordinating medical disembarkation of people with suspected or confirmed measles for testing (if ship is unable to test onboard), medical care, and/or isolation
• Notify U.S. jurisdictional state and local health departments for passenger follow-up
• Help identify and recommend management for close contacts on board
• Share measles exposure notification letter templates for passengers or crew
• Provide media talking points if requested by ships
• Notify foreign public health partners for non-U.S. resident passengers (if applicable)
• Prevent travel by commercial airline for people with measles who intend to travel against public health advice

For questions concerning this guidance, contact Maritime Administrative Support at MaritimeAdmin@cdc.gov.

More Information

• Measles for Healthcare Professionals
• CDC's vaccine recommendations for healthcare personnel
• CDC guidance on transmission-based precautions
• Interim Infection Prevention and Control Recommendations for Measles in Healthcare Settings
• Maritime Resources: Broader CDC guidance for managing sick travelers and reporting illnesses and deaths aboard ships
• Plan for Travel | Measles (Rubeola) | CDC