Guidance for Cruise Ships on Management of Acute Respiratory Illness (ARI) due to Viral Infection

Purpose

This document provides guidance for cruise ships originating from or stopping in the United States to help prevent, diagnose, and medically manage acute respiratory illness (ARI) caused by SARS-CoV-2 (the virus that causes COVID-19), seasonal influenza virus, or RSV. This guidance will be updated as needed. As cruise ships travel worldwide, cruise ship personnel need to maintain awareness of, and be responsive to, local jurisdictional situations and requirements. Cruise ship management and medical staff need to be flexible in identifying and caring for people with ARI. The healthcare provider's assessment of a patient's clinical presentation and underlying risk factors is always an essential part of decision-making about the need for further medical evaluation, testing, and treatment.

This document also provides guidance for preventing spread of ARI during and after a voyage, including use of personal protective measures for passengers and crew members and strategies for controlling outbreaks.

Describing and defining passengers and crew with acute viral respiratory illness (ARI)

Signs and symptoms of ARIs can include acute onset of some or all of the following:

• fever or feeling feverish
• cough
• runny nose
• nasal congestion
• sore throat
• shortness of breath
• difficulty breathing
• chills
• muscle or body aches
• headache
• fatigue (tiredness)
• loss of taste or smell
• diarrhea
• vomiting

For cruise ship surveillance purposes, CDC defines ARI as an illness of presumed viral etiology with at least two of the following symptoms: fever/feeling feverish, cough, runny nose, nasal congestion, or sore throat and excluding:

• Confirmed acute respiratory infection diagnoses other than COVID-19A, influenzaB, or RSV infection C(e.g., Streptococcal pharyngitis, Epstein-Barr virus infection),D
• Diagnoses of bacterial pneumonia: either clinical or test-positive (e.g., by urine Legionella antigen, urine Streptococcus pneumoniae antigen), and
• Non-infectious conditions as determined by the ship's physician (e.g., allergies)

Fever (a temperature of 100.4°F [38°C] or higher) will not always be present in people with COVID-19, influenza, or RSV infection. Cruise ship medical personnel should consider someone as having a fever if the sick person feels warm to the touch, gives a history of feeling feverish, or has an actual measured temperature of 100.4°F (38°C) or higher.

Reducing the spread of viral respiratory infections

Commercial maritime travel is characterized by the movement of large numbers of people in enclosed and semi-enclosed settings. Like other close-contact environments, these settings can facilitate the transmission of respiratory viruses from person to person through droplets and small particles or potentially through contact with contaminated surfaces.

Efforts to reduce the spread of respiratory viruses on cruise ships should focus on encouraging crew members and passengers:

• 6 months and older to get vaccinated annually for seasonal influenza
• 6 months and older to stay up to date with their COVID-19 vaccines
• who are eligible to discuss and consider RSV vaccination with their healthcare provider
• to avoid contact with ill people before scheduled cruising
• to postpone travel if sick with ARI (passengers)
• to take steps to protect themselves and others while traveling

Cruise ship management should include:

• Encouraging good hand and respiratory hygiene and cough etiquette
• Optimizing ventilation via use of outdoor areas and improving air quality of indoor spaces
• Early identification and isolation of crew members and passengers with ARI, consistent with CDC's respiratory virus guidance
• Use of antiviral medications for treatment of people with suspected or confirmed COVID-19 or influenza with severe or complicated illness, or at increased risk of severe illness or complications
• Use of antivirals for post-exposure prophylaxis (PEP) or during influenza outbreaks, if indicated, for people at increased risk of complications

Vaccination of crew and passengers

All passengers and crew are recommended to be up to date with all routine vaccines including vaccines for COVID-19, influenza, and RSV, when indicated. In addition to the protection vaccines for respiratory infections provide to individual travelers in preventing severe illness or death, having a high proportion of travelers on board who are up to date with these vaccines reduces the likelihood that cruise ships' medical centers will be overwhelmed by cases of ARI.

COVID-19: All people 6 months of age and older should stay up to date with their COVID-19 vaccines. For more information on COVID-19 vaccine recommendations, see COVID-19 Vaccination Interim Clinical Considerations FAQs and COVID-19 Vaccination Clinical and Professional Resources.

Seasonal Influenza: All people 6 months of age and older should be vaccinated each year with the seasonal influenza vaccine. Crew members should be vaccinated yearly. Vaccination of passengers, especially those at increased risk for influenza complications, is recommended at least 2 weeks before cruise ship travel, if the seasonal influenza vaccine is available and the person has not already been vaccinated with the current year's vaccine. For more information on seasonal influenza vaccine recommendations, see Seasonal Influenza Vaccination Resources for Health Professionals.

RSV: Eligible travelers should discuss RSV vaccination with their healthcare provider prior to cruise travel. For more information, see Clinical Overview of RSV.

Viral ARI screening procedures for embarking passengers

Cruise ship operators can consider:

• screening embarking passengers for viral ARI symptoms
• performing viral testing (e.g., COVID-19, influenza, RSV) for passengers with ARI symptoms before they embark. Ships that choose to use COVID-19 antigen tests should follow FDA guidance.
• denying boarding for passengers who test positive for infectious viral etiologies during pre-embarkation screening. If boarding is permitted, see guidance for isolation and other measures

If the cruise ship operator chooses to test for other infectious etiologies and testing identifies an alternate etiology (e.g., Legionella, Epstein-Barr virus, Streptococcal pharyngitis) through laboratory testing, routine infection control precautions specific to the diagnosis should be followed.

Managing cruise travelers with ARI and contacts while on board

Travelers with ARI who board, as well as those who become sick with ARI onboard, should be identified and tested as soon as possible to minimize transmission of respiratory viruses. The table below provides recommendations for management of persons on board with COVID-19, influenza, or RSV infection, and those exposed (i.e., contacts).

Managing passengers or crew with ARI upon disembarkation

Disembarking cruise ship passengers or crew members who have ARI should continue to take precautions after disembarkation. If a passenger or crew member with viral ARI is transferred from the ship's medical center to a healthcare facility off the ship, the facility should be informed before arrival. Medical transport providers should also be notified in advance.

Medical evaluation and management

Medical centers on cruise ships can vary widely depending on ship size, itinerary, length of cruise, and passenger demographics.

• Cruise ship medical centers are recommended to follow the operational guidelines published by the American College of Emergency Physicians (ACEP) as well as disease-specific clinical guidelines (see Additional Resources).
• To reduce the spread and severity of ARI, cruise ship medical centers should carry a sufficient quantity of personal protective equipment (PPE), medical, and laboratory supplies:
  • PPE: surgical masks and NIOSH Approved® N95® filtering facepiece respirators or higher, eye protection such as goggles or disposable face shields that cover the front and sides of the face, and disposable medical gloves and gowns
  • Antiviral agents and other therapeutics for COVID-19, influenza, and RSV infection (if commercially available), and other antimicrobial medications
  • Antipyretics (e.g., acetaminophen and ibuprofen), oral and intravenous steroids, supplemental oxygen
  • Onboard capacity to conduct viral tests for SARS-CoV-2 and influenza, and RSV, as well as other infections that may be in the differential diagnosis (e.g., group A Streptococcus, Streptococcus pneumoniae, Legionella)
• Medical center staff should adhere to standard and transmission-based precautions when healthcare personnel are caring for patients with suspected or confirmed COVID-19, influenza, RSV, or other communicable diseases.

For more information, read updated resources for clinicians and guidance on the medical evaluation and management of people with COVID-19, seasonal influenza, or RSV.

Diagnostic tests for acute viral respiratory illness (ARI)

Respiratory specimens for ARI testing should be collected immediately upon illness onset, with the understanding that repeat testing may be indicated based on the viral etiology or epidemiology of circulating respiratory viruses. In general, molecular tests are recommended over antigen tests because of their greater sensitivity; multiplex assays are available that can detect SARS-CoV-2, influenza A and B, and RSV.

Healthcare providers should understand the advantages and limitations of rapid diagnostic tests, and proper interpretation of negative results of any antigen diagnostic tests. Rapid antigen diagnostic tests have a lower sensitivity compared with molecular tests, and false negative results can occur frequently. In symptomatic persons, negative rapid antigen diagnostic test results do not exclude a diagnosis of COVID-19, influenza, or RSV; clinical diagnosis of these illnesses should be considered. However, positive test results are useful to establish a viral etiology and to provide evidence of infection in passengers and crew members aboard ships.

Respiratory and hand hygiene

People with ARI should be advised of the importance of covering coughs and sneezes and keeping hands clean because respiratory viruses may be shed after the isolation period ends.

Cruise operators should ensure passengers and crew have access to well-stocked hygiene stations with soap and water and/or hand sanitizer, tissues, paper towels, and trash receptacles.

Respirators or well-fitting masks should be readily available. After ending isolation, passengers and crew recovering from ARI should be encouraged to take precautions when outside their cabins.

Passengers and crew members should be reminded to wash their hands often with soap and water, especially after coughing or sneezing. If soap and water are not available, they can use an alcohol-based hand sanitizer that contains at least 60% alcohol.

Used tissues should be disposed of immediately in a disposable container (e.g., plastic bag) or a washable trash can.

Outbreak control

A combination of measures can be implemented to control ARI outbreaks, including initial isolation of symptomatic people, increased infection prevention and control efforts, antiviral chemoprophylaxis of influenza-exposed people, crew member and passenger notifications, and active surveillance for new cases.

Recommendations when a voyage's crew or passenger ARI attack rate reaches 3%E

• Provide all crew members with respirators or well-fitting masks and provide crew with information on how to properly wear, take off, and clean (if reusable) them.
• Maximize the introduction of outdoor air and adjust HVAC systems to increase total airflow to occupied spaces; move activities outside whenever possible. For additional information on ventilation, see Ventilation in Buildings.
• Consider outbreak notification letters to passengers and crew to allow for individual risk assessment and decision-making.
• For crew ARI attack rates ≥3%:
  • Cancel nonessential face-to-face employee meetings as well as group events (such as employee trainings) and social gatherings.
  • Maximize air circulation in crew outdoor smoking areas.
  • Close indoor crew smoking areas.
  • Eliminate self-serve dining options at all crew and officer messes.
  • Reduce the dining cohort size for crew, and shorten dining times to avoid crowding.

• If a COVID-19 outbreak (i.e., if the crew or passenger ARI attack rate is ≥3% with the majority of cases lab-confirmed as, or epidemiologically linked to, COVID-19):
  • Consider contact tracing for focused testing and/or additional mitigation measures for those at highest risk.
  • For crew outbreaks, consider serial viral (antigen or molecular) screening testing of crew every 3–5 days. The onboarding of additional laboratorians may be needed to facilitate the testing process.
• If an influenza outbreak, (i.e., if the crew or passenger ARI attack rate is ≥3% with the majority of cases lab-confirmed as, or epidemiologically linked to, influenza A or B):
  • Perform contact tracing.
  • Consider antivirals for prevention of influenza in exposed people, depending on their risk for complications, or all identified contacts onboard.

Considerations for suspending passenger operations

In some circumstances, additional public health precautions, such as returning to port immediately or delaying the next voyage, may be considered to help ensure the health and safety of onboard travelers or newly arriving travelers.

A ship should consider suspending operations based on the following factors:

• Sustained transmission of ARI, defined as a voyage with:
  • 15% or more of the passengers have met ARI criteria; or
  • 15% or more of the crew have met ARI criteria; or
  • 15% or more of total travelers have met ARI criteriaF
• Severe ARI among passengers or crew resulting in:
  • Shortages of supplemental oxygen or other medical supplies related to management of patients with ARI, or
  • 3 or more deaths due to ARI in passengers and/or crew during a voyage
• Potential for ARI cases to overwhelm onboard medical center and/or public health resources, defined as the inability to maintain:
  • Adequate staff to:
    • Evaluate symptomatic travelers and their close contacts,
    • Conduct appropriate testing of travelers,
    • Conduct routine medical checks of travelers in isolation, or
    • Conduct contact tracing of close contacts, if applicable
  • Adequate supplies of:
    • PPE,
    • Testing equipment,
    • Antipyretics (fever-reducing medications such as acetaminophen and ibuprofen),
    • Antivirals and other therapeutics for COVID-19, influenza, and RSV infection (if commercially available),
    • Oral and intravenous steroids, or
    • Supplemental oxygen
  • Inadequate onboard capacity to fulfill minimum safe manning or minimal operational services, including but not limited to housekeeping and food and beverage services
  • A new respiratory virus, strain, or variant with potential for increased severity or transmissibility identified among cases on board

Reporting

CDC requests that cruise ships submit a cumulative ARI report (even if no ARI cases have occurred) preferably within 24 hours before arrival in the U.S.G, and sooner if a voyage's crew or passenger ARI attack rate reaches 3%H. These reports are requested by completing the Cruise Ship Cumulative Acute Respiratory Illness (ARI) Reporting Form. Access to the online reporting form has been provided to cruise lines by CDC. Cruise lines that do not have access may contact CDC (email maritimeadmin@cdc.gov).

In addition, CDC emphasizes that any deaths—including those caused by or suspected to be associated with influenza, COVID-19, RSV infection, or ARI—that occur aboard a cruise ship destined for a U.S. port must be reported to CDC immediately. Report ARI deaths by submitting an individual Maritime Conveyance Illness or Death Investigation Form for each death.

Vessel captains may request assistance from CDC to evaluate or control ARI outbreaks as needed. If the ship will not be arriving imminently at a U.S. seaport, CDC maritime staff will provide guidance to cruise ship officials regarding management and isolation of infected people and recommendations for other passengers and crew members. CDC staff may also help with disease control and containment measures; passenger and crew notifications; surveillance activities; communicating with U.S. state, territorial, or local public health authorities; obtaining and testing laboratory specimens; and provide additional guidance as needed.

Infection prevention and control

Infection prevention and control (IPC) are critical to reducing the spread of ARI. Each cruise ship should maintain a written Infection Prevention and Control Plan (IPCP) that details standard procedures and policies that specifically address infection prevention and control and cleaning/disinfection procedures to reduce the spread of ARI.

To reduce the spread of ARI, cruise ship operators should include the following as part of a written IPCP:

• Duties and responsibilities of each department and their staff for all passenger and crew public areas
• A graduated approach for escalating infection prevention and control measures in response to ARI cluster or outbreaks during a voyage with action steps and criteria for implementation
• Procedures for informing passengers and crew members that a threshold of ARI has been met or exceeded, and of any recommended or required measures to prevent spread of infection
• Procedures to protect crew from occupational exposures to respiratory viruses, including crew responsible for cleaning potentially contaminated surfaces, laundry staff, and those entering cabins or other areas where people with confirmed or suspected respiratory virus infections are present
  • Crew members entering cabins or other areas where people with ARI are should be limited, and crew should wear an NIOSH Approved® N95® filtering facepiece respirator or higher in accordance with the Occupational Safety and Health Administration's (OSHA) Respiratory Protection standard (29 CFR 1910.134)
• Disinfectant products or systems used, including the surfaces or items the disinfectants will be applied to, concentrations, and required contact times
• Procedures to protect passengers and crew from exposure to disinfectants, if not already included in the ship's safety management system. At a minimum, this should include the following:
  • Safety data sheets (SDSs)
  • PPE recommendations for crew, which may include surgical masks or NIOSH Approved® N95® filtering facepiece respirators or higher, eye protection such as goggles or disposable face shields that cover the front and sides of the face, and disposable medical gloves and gowns in addition to those recommended by the disinfectant manufacturer in the SDS; for information on health hazards related to disinfectants used against viruses, see Hazard Communication for Disinfectants Used Against Viruses.
  • Health and safety procedures to minimize respiratory and dermal exposures to both passengers and crew, when recommended
• Graduated procedures for returning the vessel to normal operating conditions after a threshold of ARI has been met, including de-escalation of cleaning and disinfection protocols

Frequent, routine cleaning and disinfection of commonly touched surfaces with an Environmental Protection Agency (EPA)-registered disinfectant is recommended.

Additional resources

• Respiratory Virus Guidance
• COVID-19 Treatments and Medications
• Seasonal Influenza Prevention
• Seasonal Influenza Treatment: What You Need to Know
• Infectious Diseases Society of America guidelines for controlling institutional influenza outbreaks
• Symptoms of RSV (Respiratory Syncytial Virus)
• How RSV Spreads

Attribution Statement

N95 and NIOSH Approved are certification marks of the U.S. Department of Health and Human Services (HHS) registered in the United States and several international jurisdictions.