UK MCA: Prevention of infectious disease at sea

In light of the above, UK Maritime and Coastguard Agency issued guidance, providing information and recommendations on the causes and prevention of infectious diseases onboard ships.

Among others, the Marine Guidance Note 652 “Prevention of infectious disease at sea” includes:

• Appropriate immunisations against infectious diseases likely to be encountered by seafarers in the course of their duties.
• Specific requirements for prevention of insect borne diseases including malaria.
• Infections encountered in the seafarer’s home country or whilst on shore leave are mostly outside the scope of this document.
• Where to get further advice.

Infection risks

The risk of contracting an infectious disease will depend on a number of factors. Hence requirements are determined by assessing the risk posed by:

1. The route of the vessel, especially the location of ports visited, length of stay and likelihood of exposure ashore either on shore leave or when joining or leaving a vessel.
2. Known health risks in the country of origin of seafarers and countries passed through en route to joining or leaving the ship.
3. The role of each seafarer.
4. The hygienic and clinical preventive measures taken.

According the the Marine Notice:

Within Europe, USA and Canada, Japan, Australia and New Zealand the risks are usually no greater than those onshore in the UK and no immunisations over and above those given to the general population are recommended. It is important in any case to ensure that these general immunisations are in date. This situation is of course subject to change over time.

Job related risks

An informed clinical risk assessment is required with respect to vaccination for some diseases in some or all crew members, taking into account the nationality and origin of both crew and passengers and the route of the vessel. Stringent hygiene measures should remain the mainstay of prevention of infection, however.

Maintenance of Sewage Systems – seafarers whose work involves maintaining shipboard sewage systems are at increased risk of faecal contamination. Immunisation against hepatitis A is recommended for workers at risk of repeated exposure to raw sewage following a local risk assessment. In areas where typhoid is endemic vaccination for typhoid should also be considered.

Food Handlers – These seafarers will, if infected, pose a risk of transmitting foodborne infections to other crew members or passengers although immunisation for food handlers is not routine in the UK. They should have typhoid and hepatitis A immunisation if they originate from or are working in an area where these infections are likely.

Cruise Liners – Where large numbers of susceptible passengers are carried, as on cruise ships, outbreaks of influenza can be severe in terms of time off work and risk to passengers, and crew immunisation should be considered.

Night Work – Crew who are required to spend periods on deck, particularly at night, in places where malaria is rife, will be at high risk of mosquito bites, and bite avoidance with correct use of antimalarial tablets is particularly important.

Travel Away from Vessel – If a seafarer is planning to spend time away from the ship and harbour area either on business or for leisure, additional advice is needed before departure on whether the precautions used on account of the ship’s voyage remain adequate.

Crew Providing Medical Care – Health professionals working on board ship should be fully immunised, including confirmed protection from hepatitis B. The provision of routine hepatitis B immunisation may need to be considered if non-health care specialists are regularly required to provide such care.

Insect borne diseases

Anyone who falls ill whilst in or after leaving an area with risk of these conditions should inform a doctor immediately that they have been exposed to risk of insect borne infection.

This applies up to twelve months of return from a malarial area, and it is particularly important to seek urgent diagnosis and treatment for any feverish illness even when preventative treatment has been taken.

Avoidance of insect bites should be the mainstay of prevention in tropical areas. Although specific preventative measures are available for malaria and yellow fever, this is not the case for other infections, and failure of treatment is a possibility.

• Wear long-sleeved shirts and long trousers when going on deck or ashore particularly after dusk when mosquitoes are most active.
• Use insect repellent on any exposed skin.
• Keep openings (e.g. doors, portholes, ventilators and hatches) closed where possible.
• Use mosquito wire-screening and nets on any openings.
• Use anti-mosquito preparations or insecticides, treating compartments with insecticide spray and killing any mosquitoes found.
• Use filtered air conditioning where available.
• If seafarers need to stay ashore in non-air-conditioned accommodation, beds should have nets. Nets should preferably be impregnated with permethrin, and well tucked in with no tears or holes.