Textbook of Maritime Medicine

Vaccinations are a highly effective method of preventing certain diseases. Vaccinations in travellers are globally seen as one of the safest methods to avoid a range of dangerous infections that may be encountered abroad. Most seafarers will have received childhood vaccinations through routine immunization programs in their home countries. However, our experiences teaches us that seafarers rarely carry evidence of childhood vaccines with them and often are not aware of vaccinations received as children. 

Globally, national programs do recommend vaccinations in children. Most of those programs follow WHO recommendations as a minimum standard (WHO 2009). However, coverage rates differ substantially between countries (WHO/UNICEF Immunization Summary 2008) depending on prioritization and organization of national programs, financing issues and sociocultural factors. Thus, in the individual seafarer immunity to vaccine preventable diseases can not be assumed to have been provided by childhood immunizations. Immunizations for certain occupational groups and for travellers are recommended by scientific organizations, governments and the Wold Health Organization.

Employers may require certain vaccinations in their employees as a prerequisite for employment. In the shipping industry there is traditionally strict observance of vaccinations that are mandatory or believed to be mandatory for entry to countries to be visited,  such as against Yellow Fever (required for international travel in certain areas by WHO´s International Health Regulations 2005), Cholera or Meningococcal Disease (currently or formerly required by some national governments). However, only well organized shipping companies will have malaria prevention and immunisation policies that go beyond satisfying international requirements. Often, companies and shipmasters will not consider further vaccination to cover specific occupational risks such as Hepatitis A, Chickenpox, Measles or Influenza. This is the case with many if not most companies despite a known or assumed occupational risk of disease. Frequently, the need of immunization for the prevention of diseases and to avoid loss of work days in an individual seafarer or outbreaks of diseases which may endanger the ship´s safety (Schlaich 2008) is unknown or neglected.

The medical moctor who performs a pre-employment exam, is responsible for port health control, who gives for travel advice or who treats seafarers will need to be aware of

-   the specific medical risks of the area where the ship is sailing,

-   national and international recommendations and requirements

-   the company’s policy regarding vaccinations

-   specific occupational risks

-   individual risks

-   hygienic and medical conditions on board

He also will need to be able to consult the seafarer on how to receive safe follow-up injections during his travel to gain full immunity.

Furthermore the medical doctor needs to advixe the seafarers about risks in the period before the vaccine will become fully effective.

The medical doctor should advise the seafarer and the company on the grounds of scientific evidence but on the same time be aware of the complexity of the issue in the maritime environment. It is the Medical Doctor’s obligation to inform the seafarer on benefits and risks of the vaccination (preferably by written and oral information in the seafarers native language, alternatively in English). It should be clearly communicated to the seafarer and the company and documented in writing if a vaccine is recommended on the grounds of the occupational health risks (such as Tetanus, Hepatitis A and B, Influenza, Yellow Fever, Meningococcal, Typhoid or Chickenpox Vaccines) and/ or mandatory by national or requirements (such as Yellow Fever, Meningococcal, Typhoid or Cholera Vaccines). If a vaccine is required by the company’s policy, such as Cholera or Yellow Fever but not indicated because of the current travel route this has to be communicated to the seafarer and company. However, the medical doctor will have to take into consideration the area of operation of the company and the degree of flexibility the ship’s management requires in terms of crewing and routes. Given the overall excellent safety profile of vaccines, the medical doctor will be able to recommend a vaccination in most cases if individual risks (contraindications) are clearly ruled out. Individual decision making is needed if the seafarer claims that he or she has received a vaccine before without this having been documented.

Depending on the company or the national immunization policies the fees for certain vaccination will be covered by governmental funds, the employer, health insurances or the vaccinee him/herself. The medical doctor should be aware of the specific modes of financing and consult the seafarer accordingly.

7.7.1 Vaccination Requirements

Generally speaking, the recommendations for immunisation and prophylaxis will depend on the occupational infection risks and on national and international immunization requirements which mainly focus on the prevention of the spread of the disease.

Infection risks in a seafarer will depend on individual immunity of a seafarer (against diseases such as Hepatitis A, Measles or Chickenpox by natural immunity or childhood immunization)

   -  the ports visited (such as areas of Yellow fever infection or where the mosquito vector is
      present)

   -  duties undertaken (such as maintenance of sewage systems, providing medical care)

   -  living conditions on board (such as single or multiple accommodation)

      “mix” of persons onboard  (mix of persons from high and low endemicity areas for certain
       diseases or contact with a large number of persons on board passenger ships including
       children and elderly persons)

   -  availability of medical and hygienic preventative measures
       treatment in case of an influenza outbreak, availability of disinfection)
       extent of travel away from ship (such as travel in rural areas)

The most reliable source of information in the global environment of shipping is WHO´s publication on International Travel and Health (WHO 2009) which is updated yearly.

Based on the traveller’s individual risk assessment, a health care professional can determine the need for immunization. The medical doctor advising the seafarers and their employer may evaluate the immunization requirements in an individual seafarer using the following categories:

• Routine childhood immunizations to be recommended in all seafarers.
• Routine immunizations for adults to be recommended to all seafarers.
• Mandatory immunizations that may be required for travel to certain areas (mainly Yellow Fever)
• Additional immunizations to be recommended depending on occupational risks and travel to disease-endemic areas.

Safe injection techniques are to be used as recommended by WHO. WHO recommends the use of single-use syringes and disposable mono dose preparations whenever possible. For documentation of the immunization the “Model International Certificate of Vaccination or Prophylaxis” as given in Annex 6 of the International Health Regulations 2005 is to be used. It is mandatory to clearly display the brand name of the vaccine, the manufacturer and batch no., dose, date, name and address (stamp) of clinician.

Vaccines that may be indicated

Complete Childhood immunizations, if appropriate

Booster doses Tetanus every 10 years

Booster doses Diphtheria every 10 years

Influenza and pneumococcal disease

in the elderly

Yellow fever (required under IHR 2005 in affected areas, see county list at www.who.int/wer)

Meningococcal Disease required by Saudi-Arabia for certain destinations

Cholera

Hepatitis A

Japanese encephalitis

Meningococcal Disease

Rabies

Tick-borne encephalitis

Typhoid fever

Poliomyelitis

Yellow Fever

Hepatitis A

(Food Handlers, Maintenance in Sewage System)

Hepatitis B (providing medical care)

Typhoid (food handlers)

Chickenpox, measles, rubella (if children on passenger ships represent)

Influenza (passenger ships)