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How to do a travel health risk assessment

Carolyn Driver
RGN RM RHV FPCert MSc(TravelMed) FFTM RCPS(Glas)
Independent
Travel Health
and Immunisation Specialist Nurse
Cheshire

A travel health consultation is a health promotion activity. It is not a simple matter of looking at a destination to determine risk; rather it is necessary ato perform a detailed risk assessment to determine the most significant risks to the individual's health on their particular trip. Destination is only one small part of this process. Cardiovascular disease and trauma are the most significant causes of death in travellers. Trauma accounts for the most significant amount of morbidity in tourists from industrialised countries.(1) Vaccine-preventable diseases represent only a small proportion of infectious causes of morbidity in travellers, so it is important that other hazards and preventive strategies are highlighted.(2) Preexisting medical conditions may place some travellers at greater risk of these issues and therefore their individual needs must also be addressed.

Risk assessment
Ideally the risk assessment starts before the consultation with the traveller having been asked to bring all relevant information with them. A questionnaire may be sent for them to fill in beforehand or they should be prompted when making the appointment to bring with them details of itinerary, vaccination history, and so on. Ideally the risk assessment should occur six to eight weeks before travel, but it is never too late to offer useful advice and to administer some vaccinations and chemoprophylaxis.
For a useful risk assessment to be performed there needs to be sufficient time to allow for it and the administration of relevant vaccines and advice. The traveller should also be aware of how long they are likely to be in the clinic so that they do not try to rush the process. Twenty minutes is considered to be the minimum in which this can be done and this must be multiplied at least once if a couple or family is travelling.(3) All of the factors described in Figure 1 and Box 1 are equally important. The main preventive strategy involved in travel health is education - advising the traveller about potential hazards and how to minimise the risk to themselves of these hazards.

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Resources for the travel health adviser
Once a detailed history has been taken the adviser must have access to good up-to-date resources in order to be able to advise the traveller correctly. Online databases are the most appropriate sources of such information as they can be updated on a daily basis. Books can be a valuable source of background information, but these can quickly become out of date and thus should not be used alone. Wall charts by their very nature cannot give the detail that is necessary for a full risk assessment and also need to be replaced frequently with up- to-date versions. The National Travel Health Network and Centre (NaTHNaC) and the Malaria Reference Laboratory also run telephone helplines for healthcare professionals to ring when there are no readily available answers to challenges posed by either the traveller's history or the intended itinerary. Box 2 outlines the resources that all travel health advisers in the UK should have access to.

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Vaccination recommendations
The art of travel medicine is not to simply give all the vaccines at our disposal, but to use vaccines appropriately in conjunction with other health promotion activities. Informed consent must be obtained and in order to do this the patient should be informed about the disease, its mode of transmission, consequences of infection, and, in the travel context, endemicity at their destination. Any possible adverse effects of the vaccine should also be described. Many diseases that we can prevent with vaccination are quite rare in travellers, but should they occur could be very serious or indeed fatal to the individual. It is important that the traveller understands the context in which vaccination is being recommended and that despite being vaccinated there will still be a need for additional precautions. For example, vaccinating against hepatitis A and typhoid does not protect against the far more common food- and waterborne infections such as travellers' diarrhoea. Vaccination against yellow fever does not offer protection from the myriad of other mosquito-borne infections.
In general vaccines fall into three distinct groups:

  • Routine - part of the national schedule in the country in which the individual usually lives.
  • Required - compulsory for entry to a particular country.
  • Recommended - those that may be considered for the type of traveller or destination concerned.

Routine
A travel consultation is always an ideal opportunity to check that an individual has completed their primary vaccination series.
In the UK we do not normally boost diphtheria, tetanus and polio once a person has received a total of five doses. This is because they are at negligible risk of coming into contact with either diphtheria or polio and it is assumed that if they sustain a tetanus-prone wound that they will receive appropriate postexposure care. This may not be the case when they travel abroad. For this reason it will be a recommendation for many destinations that those who received their last dose of one or more of these antigens more than 10 years ago should receive a booster. Currently the recommended product to use in this situation regardless of which antigen is required would be Revaxis by Sanofi Pasteur MSD (combined tetanus, low-dose diphtheria and polio vaccine).(4) Children who are up-to-date with the national schedule according to their age do not need additional doses of these vaccines for travel purposes.

Measles
Long-stay travellers to areas where there is a high prevalence of measles infection (Africa and South East Asia) or a current epidemic should have their history of measles infection or immunity checked. Adults born between 1970 and 1979 may have only received one measles vaccine and had little exposure to the natural virus so they may be particularly susceptible. If such individuals have no clear history of measles infection they should be offered MMR vaccination or have blood taken to check for measles antibody. Anyone born later than this who is unsure of having received two measles-containing vaccines should follow the same protocol. Individuals born before 1970 are likely to have been naturally exposed to measles.
Infants between six and 12 months who are being taken to measles endemic countries can be given MMR, but this will be an extra dose and they should still receive two doses at the appropriate age within the national schedule. Children who have received the first, but not the second MMR, and who are travelling to endemic areas should have the second dose brought forward. If they receive the second dose before the age of 18 months it is recommended that they receive an additional dose with the preschool booster as per the national schedule.(4)

Required vaccines
Currently the only vaccine for which there may be a compulsory requirement under the International Health Regulations is yellow fever. In fact very few countries require all visitors to have a certificate. Most countries only have a requirement for those entering from an infected country. It is important that the adviser ensures that people who are travelling to countries where yellow fever is endemic are advised to receive vaccination regardless of the certificate requirement. The International Health Regulations were put in place to stop the spread of disease from one country to another rather than to protect individuals. Thus the emphasis is on restricting people who are travelling from a country where a disease exists into another which may be susceptible to that disease. Full information about yellow fever along with maps of the endemic areas can be found on the NaTHNaC website under "Health Information/Yellow Fever". Read all about yellow fever on page 15 in this issue of Nursing in Practice.

Meningitis ACWY
Travellers who visit Saudi Arabia for the purpose of attending either the Hajj or Umra pilgrimages are required to have a certificate of vaccination against meningitis ACWY. This is a local measure introduced after a major outbreak of meningitis at the Hajj some years ago. Millions of travellers converge on the city of Mecca for the pilgrimage, many of whom travel from the meningitis belt of West Africa. The disease proliferates in the very overcrowded and dry atmosphere of this event; however, since this important disease control measure was put into place no such outbreaks have occurred.

Recommended vaccines
The vast majority of available vaccines are only recommended and the decision whether or not to receive them rests with the traveller. The travel health adviser should facilitate patient choice. While the focus is often on destination and length of stay for the upcoming trip it is important to look at planned activities and also future travel plans when making recommendations. There may be cumulative risk or it may be that the actual purpose of the trip puts the individual at high risk even though the duration of travel is quite short. This is a specific area of the consultation where access to adequate resources is very important.

Malaria and bite avoidance
The guidelines produced by the Advisory Committee on the prevention of malaria in UK travellers is a very
user-friendly document that anyone who advises travellers should read (see Box 2). Its Q&A section outlines most of the common situations that travellers bring to a consultation and there are equally useful sections on bite avoidance and chemoprophylaxis. It is important for healthcare professionals to ensure that any future updates are received promptly and this involves keeping a regular check on websites such as NaTHNaC and TRAVAX. Malaria prevention needs to be discussed with the traveller in order to ensure compliance with recommended measures and it is a mistake to think that this part of the consultation can be covered by merely issuing a prescription.

The last-minute traveller
It is a common myth that there is little that can be done for the traveller who seeks advice only a day or two before departure. Advice is never too late and all the lifestyle issues referred to in Box 1 are amply covered by NaTHNaC, TRAVAX or fitfortravel where downloadable advice sheets can be printed off and given to travellers.
Booster doses of vaccines work rapidly so it is never too late to give a booster. Hepatitis A has a long incubation period so it is perfectly in order to use this vaccine right up until the day of departure as there would still be time for an antibody response to be mounted even if the traveller were exposed to the virus at the start of their trip.(4) For other vaccines a decision needs to be made on the basis of risk, the length of the trip and possibility of completing courses during travel. All options should be discussed with the traveller and where vaccination is considered inappropriate or is refused this should be documented and alternative measures for reducing the risk of infection should be discussed. With regards to malaria prophylaxis both atovaquone and proguanil, and doxycycline can be started just before travel and thus are ideal for the last-minute traveller. The malaria guidelines give full details of these drugs and their use in last-minute travellers.

Conclusion
Travel health advice involves much more than merely administering vaccines and malaria prophylaxis. Time is required to provide a comprehensive approach to care, and up-to-date resources are vital for ensuring that the traveller is benefiting from the correct information.

References:

  1. Steffen R, deBernardis C, Banos A. Travel epidemiology - a global perspective. Int J Antimicrob Agents 2003;21:89-95.
  2. Gezairy HA. Travel epidemiology: WHO perspective. Int J Antimicrob Agents 2003;21:86-8.
  3. Royal College of Nursing Travel Health Forum. Delivering travel health services. RCN guidance for nursing staff. London: RCN; 2005. Available from: http://www.rcn.org.uk
  4. Department of Health. Immunisation against infectious disease 2006 (The Green Book). London: DH; 2006.