Dr Dipti Patel discusses key potential hazards and challenges, which could initially appear harmless, that should be considered when carrying out a risk assessment for business or leisure travel.
Risk assessment is an integral part of pre-travel assessment, and largely determines the advice and interventions given to the traveller. It is the process by which one identifies the hazards that a traveller might be exposed to, evaluates the risk associated with those hazards and determines how to manage them.
The art of risk assessment is to identify and characterise material risks to health that may require control, taking into account both the seriousness of potential outcomes as well as their likelihood.
Epidemiology of travel-related illness
One of the challenges of determining risk of illness is that understanding of the epidemiology of travel-related disease is limited. Figures for disease risk in travellers can not be accurate because it is difficult to ascertain the exact numbers of travellers to specific destinations, or the cases of illness or injury in travellers.
Furthermore, a great deal of the commonly quoted statistics regarding the incidence of illness or injury in travellers are based on the extrapolation of limited data, collected from morbidity studies, which vary in methodology. These studies have mostly focused on specific diseases, travellers to tropical destinations or specific traveller groups.
For overseas travellers, the risk assessment requires knowledge of the traveller, their itinerary, their destination, the potential health risks and diseases, and the available preventive measures.
Three broad categories need to be considered: individual; itinerary and destination; and activity-related factors. In the case of those who are travelling for work purposes, the latter will also include consideration of occupational hazards. Box 1: Factors to consider during the risk assessment summarises some of the key information that should be considered as part of the risk assessment.
The risk assessment should ideally be performed four to six weeks before travel, possibly earlier for those who are travelling for a prolonged period, have a complex itinerary, or complex medical history. This will allow adequate time for completion of vaccinations, monitoring for adverse reactions, and also allow the traveller to mount an adequate immune response to vaccine-preventable diseases. However, last-minute travellers can still benefit from a pre-travel assessment.
For efficiency, risk assessment information can be gathered by asking travellers to complete a risk assessment form prior to their appointment – a number of standardised questionnaires exist.
Information on the traveller that should be considered is summarised in box 1. A detailed medical history is essential because the traveller’s pre-existing physical, psychological, immunological and medical status, together with their personality, experience, and behaviour while overseas will affect their risk of illness or injury. The following factors need to be considered:
- Age. The traveller’s age is an important consideration in the risk assessment. For example, young children may be more vulnerable to certain travel-related hazards, illness may be more difficult to recognise, they may not have completed their childhood vaccinations, and certain preventive measures such as malaria prophylaxis or vaccines may not be suitable (for example, doxycycline is contra-indicated in children under 12 years, and cholera vaccine is contra-indicated in children under the age of two years). Older travellers may have been born before the availability of certain national schedule vaccines, and due to immunosenescence, their ability to respond to infection or vaccination may be reduced. In some instances, the risk of adverse events related to vaccines may be increased, as is the case in yellow fever vaccination in primary vaccinees over the age of 60. Furthermore, pre-existing medical conditions and the reduced ability to adapt to different environments can increase risk of morbidity and mortality in this group.
- Gender. For example, young men may be more likely to indulge in risk-taking behaviours with a potential for accidents, injury, or casual sexual encounters; whereas for women, personal security may be more of a concern.
- Medical history. Where pre-existing health issues are identified, not only must the stability of the condition and any impact it has on functionality be considered, but the efficacy of preventive measures, the impact of travel, the overseas environment, the adequacy of local medical facilities and – in some cases – the availability of medication/medical equipment must also be considered.
Conditions that may not be of any concern in the UK may be problematic overseas. For example, an individual with asthma may find that their condition is exacerbated in a polluted city such as Beijing; someone with diabetes who takes insulin may find that their glucose control is affected by hot climates; and an individual on warfarin, and who is on a long-term trip to South-East Asia, may find that reliable international normalised ratio (INR) monitoring is not available consistently.
In the case of immunosuppression (whether due to disease or treatment), the ability to respond to certain infectious diseases may be affected, response to vaccines may be reduced, and live vaccines are often contra-indicated.
There may be a potential for interaction of medications with recommended vaccines or malaria prophylaxis (for example, malaria chemoprophylaxis may interact with antiretrovirals), there may be considerations in relation to transport of prescribed medicines across international borders, or a need to adjust medication (for example insulin) across several time zones.
In the case of long-term travel, consideration will need to be given to whether or not the traveller will have access to adequate supplies of their medication, including the possibility of obtaining medication at their destination.
Travel during pregnancy requires special consideration. Factors such as the presence of complications, gestation at the time of travel, the suitability of vaccines and malaria prophylaxis, the impact of infectious diseases, such as malaria and hepatitis E (which can be particularly problematic during pregnancy), and the availability of obstetric and neonatal care at the destination will need to be considered.
Finally, evaluation of individual risk factors will need to be considered in the context of airline or travel insurance policies. For the former, there may be some restrictions on flying (for example, most commercial airlines restrict flying after the 36th week of pregnancy); and for the latter, careful research is required as the coverage afforded travel insurance can vary, and there may be specific exclusions where pre-existing health conditions are identified.
The hazards of the destination are an integral part of the travel risk assessment, and will include consideration of destination-specific endemic diseases, security issues, social/cultural differences, climate and environmental risks.
Consideration will also need to be given to any restrictions imposed by the destination such as certificate requirements for vaccinations (for example, in the case of yellow fever vaccination or less commonly polio vaccine), or restrictions of entry to those with certain communicable diseases, such as HIV.
Information on the hazards associated with the destination and any specific requirements for travel to that destination may be obtained from a variety of sources. Due to the dynamic nature of destination-related risks, access to up-to-date references and online resources are essential to ensure real-time and validated information on the global infectious disease and other health risk distribution, the changing patterns of infections and drug-resistant organisms, advances in preventive health measures, and country-specific health regulations.
In the UK, there are two national resources for country-specific travel health information: the National Travel Health Network and Centre; and TRAVAX. Some important sources of information are shown in box 2.
When considering the destination, it is important to know the exact itinerary and precise intended destinations because disease or safety hazards may vary within a country or even within a region.
Details of stopovers are also important as they may have an impact on recommendations. Knowledge of the geography and climate of the destination – whether it is rural, urban, coastal, jungle, savannah, desert, at altitude, humid or dry – will help inform the risk assessment. For example, in a desert environment one may need to consider: extremes of temperature; areas of high humidity and high ambient temperatures, which provide optimum conditions for malaria transmission; rainfall, which increases mosquito breeding; and the risk of altitude illness for those ascending to elevations above 2,500 metres.
Evaluating planned activities while overseas is also essential. The hazards encountered by someone going for a short city break in Spain, will be different from those facing a traveller on an all-inclusive holiday in the Caribbean, or a work trip to a remote location in northern Kenya.
While it is difficult to generalise, it is likely that luxury travellers on a well-organised trip, with a pre-determined itinerary will be at less risk than those on a restricted budget. They are more likely to have access to clean drinking water, sanitation, air-conditioning and mosquito nets.
Budget travellers, on the other hand, may not be so fortunate and also may chose to forgo certain preventive measures such as vaccines due to the prohibitive cost. However, even during a luxury holiday, certain planned activities may alter the risk profile, for example planning to participate in activities such as scuba diving or white-water rafting – particularly if poorly supervised – may increase the risk of injury.
Activities where particular attention is required are highlighted in box 1. In the case of adventure travel, the traveller may choose to take part in hazardous activities; backpackers may be travelling for longer periods on a low budget to less well developed countries; business travellers may have had little time to prepare for their trip, may have little control over where they travel or may be exposed to specific occupational hazards associated with their work.
Longer-term travellers will have a longer cumulative exposure to country-related hazards, closer contact with the local environment and population, and complacency regarding their environment, thus increasing their risk of illness or injury; and those travellers visiting friends or relatives may underestimate the risks they are exposed to, and may not appreciate the need to get pre-travel advice.
The final aspect of the risk assessment is to consider the risk of any travel health interventions and advice. This may be something that is overlooked, but it is important to consider whether the risk of the exposure to the hazard justifies the risk of the intervention or even the cost of the intervention.
Interventions such as malaria chemoprophylaxis and vaccinations are not without adverse effects and can be costly, and will need careful evaluation and discussion with and traveller.
Risk assessment is an integral component of the pre-travel health assessment, and will help reduce the risk of illness or injury in travellers. It allows the identification of potential health risks, and helps determine the advice and preventive strategies for the traveller.
The key to risk assessment is to identify and characterise material risks to health that may require control, and to allow the traveller to make informed decisions and choices regarding preventive measures and interventions without unnecessary adverse events, cost or inconvenience.
Chiodini J, Boyne L, Stillwell A,Grieve S (2012). “Travel health nursing: career and competence development”. RCN guidance. RCN: London.
Field VF, Ford L, Hill DR, eds (2010). “Health Information for Overseas Travel”. NaTHNaC, London, UK.
WHO, Geneva (2012). “International Travel and Health”.
Box 1: Factors to consider during the risk assessment
- Medical history
- Drug history
- Vaccination history
- Previous experience of travel
- Attitudes to risk
Itinerary and destination factors
- Dates of travel
- Duration of trip
- Type and style of travel
- Country/countries and regions being visited
- Endemic diseases
- Medical care
- Cultural/legal considerations
- Safety and security
- Geography and environment
Planned activities/purpose of travel
- Adventure activities (diving/extreme sports/skiing etc)
- Budget/luxury travel
- Last-minute travel
- Long-term travel
- Medical treatment/tourism
- Sex tourism
- Visiting friends and relatives
- Work – business traveller/aid worker/volunteer/expatriate
Box 2: Sources of information
Commercial databases include:
- International SOS online country guides
- Travax Shoreland
Emerging diseases and outbreaks
Other useful resources
- Guidelines for malaria prevention in travellers from the United Kingdom 2013. Public Health England
- Health Information for Overseas Travel. NaTHNaC, 2010 (UK Yellow Book)
- Immunisation against infectious diseases (UK Green Book).
- Information for International Travel. CDC, 2013 (US Yellow book)
- International Travel and Health. WHO, 2012
- Foreign and Commonwealth Office (safety and security).