The data were presented in poster form at the 4th Northern European Conference on Travel Medicine in Dublin, 6–8 June 2012.
Corresponding Author: Elke Wynberg, Victorialaan 4, 2242 CN Wassenaar, The Netherlands. E-mail: firstname.lastname@example.org
Many studies have explored the risk perception of frequent business travelers (FBT) toward malaria. However, less is known about their knowledge of other infectious diseases. This study aimed to identify knowledge gaps by determining the risk perception of FBT toward 11 infectious diseases.
Our retrospective web-based survey assessed the accuracy of risk perception among a defined cohort of FBT for 11 infectious diseases. We used logistic regression and the chi-square test to determine the association of risk perception with source of travel advice, demographic variables, and features of trip preparation.
Surveys were returned by 63% of the 608 self-registered FBT in Rijswijk, and only the 328 completed questionnaires that adhered to our inclusion criteria were used for analysis. The majority (71%) sought pre-travel health advice and used a company health source (83%). Participants seeking company travel health advice instead of external had significantly more accurate risk knowledge (p = 0.03), but more frequently overestimated typhoid risk (odds ratio = 2.03; 95% confidence interval = 1.23–3.34). While underestimation of disease risk was on average 23% more common than overestimation, HIV risk was overestimated by 75% of FBT.
More accurate knowledge among FBT seeking company health advice demonstrates that access to in-company travel clinics can improve risk perception. However, there is an obvious need for risk knowledge improvement, given the overall underestimation of risk. The substantial overestimation of HIV risk is probably due to both public and in-company awareness efforts. Conversely, typhoid risk overestimation was statistically associated with seeking company health advice, and therefore specifically reflects the high focus on typhoid fever within Shell's travel clinic. This study serves as a reminder that a knowledge gap toward infectious diseases besides malaria still exists. Our article will explore the future requirements for more targeted education and research among FBT in companies worldwide.
Despite the advent of efficient global communication platforms, employees of major corporations are often still required to travel for business purposes. For oil and gas firms operating in remote areas, this is certainly true: Shell works in over 80 countries and territories, with 8,300 employees self-registered as “frequent business travelers” (FBT) in 2008. Exposure to infectious diseases abroad can pose significant threats to the health and safety of employees if their knowledge of risk and prevention methods is inadequate. In 2004, the European Travel Health Advisory Board's (ETHAB) European Airport Study laid the groundwork for assessing the knowledge, attitudes, and behavior toward malaria and other infectious diseases among a variety of travelers. However, the unique nature of business travel distinguishes an FBT's risk of exposure to infection from that of leisure tourists, and therefore requires further investigation.
In a recent study exploring the attitudes of business travelers toward influenza, almost half of the survey participants agreed that better travel health information should be available and, in particular, that the “company doctor” was most responsible for providing this. There is consequently a clear need not only to assess infectious disease knowledge among FBT but also to identify corporate health strategies that could improve the health and safety of all employees. Using the questionnaire originally developed for the European Airport Survey, we performed a retrospective cohort study to assess FBT's knowledge toward 11 infectious diseases. Our aim was to identify:
The level of knowledge toward infectious disease risk in the FBT's destination country;
Any association of the above with possible targets for intervention, including: demographic factors, the source of travel health advice used, and timing of travel preparation.
As outlined in Berg and colleagues' previously published work on the same FBT cohort, all employees (∼2,500) working for Shell in Rijswijk, the Netherlands, had received an email asking them to self-register if they met at least one of the following criteria of an FBT:
Travel within a company-defined region on flights of more than 4 hours, three or more times per month;
Long-distance, intercontinental business travel three or more times annually;
Business travel to high-risk destinations such as those with significant local health risks and limited availability and/or accessibility of local health care facilities. This applied to most of Shell's destination countries in Africa, Asia, and Latin America.
This process of self-registration was calculated, using travel data, to have identified 97% of FBT.
The survey was distributed between July and October 2005 to Rijswijk employees self-registering as FBT. With permission from ETHAB, their original malaria questionnaire (Q-Mal) was electronically distributed using the Apian Survey Pro 3.0 Program. The survey included a question asking participants to rank the risk of contracting 11 infectious diseases (HIV, typhoid fever, rabies, meningitis, yellow fever, hepatitis A, hepatitis B, poliomyelitis, dengue fever, cholera, and seasonal influenza) for a general traveler to their destination country. For each disease, this “perceived risk” was ranked as high, low, or no risk. Destination country was defined as the most recent high-risk malaria country the FBT had visited in the preceding 2 years, and thus each individual was only required to assess the disease risks for one country. Other questions in the survey explored demographic variables and travel health preparation factors (see Statistical Analysis). Non-responding FBT received two to three reminders within intervals of a few weeks.
Only surveys returned by FBT who had undertaken business travel to a malaria-endemic country in the preceding 2 years were included in the study. The data regarding malaria were assessed and published separately, while risk knowledge of the 11 other infectious diseases is discussed in this article.
Because of the unavailability of traveler-specific prevalence data for each infectious disease in each country, we instead compared perceived traveler risk to World Health Organization (WHO) country population prevalence maps for each disease during the relevant time period. This decision was considered valid under the assumption that travelers would be at higher risk if a disease is common among the local population and at lower risk if the local human reservoir for the disease is minimal, as outlined in WHO's International Travel and Health publication. Moreover, for countries in temperate regions, the month of travel was taken into account when determining the risk for influenza (Northern hemisphere at high-risk November–March; Southern hemisphere at high-risk April–October). The WHO prevalence data for each disease, for each country, constituted “actual risk” with which to assess the accuracy of FBT “perceived risk.” Correct assessments for disease risk were summed to produce an individual overall knowledge score (out of 11) for each FBT. Incorrect assessments were divided into underestimations and overestimations for further analysis.
In order to investigate variables potentially affecting accuracy of perceived risk, we grouped responses according to two factors: destination country and knowledge level. For destination country, we calculated a country mean of the knowledge scores for those destinations with a sufficiently large sample size (n ≥ 10) to allow comparison of risk knowledge of FBT to different regions. For knowledge level, we categorized FBT knowledge scores as low (<4), medium (4–7), or high (≥8). The chi-square test investigated association of these groups with demographic variables (age, gender, nationality, and place of residence) and business trip characteristics: length of trip (1–2, ≤28, and >28 d), time before departure that trip was planned (≤2 or >2 mo), time before departure that travel health advice was sought, if at all (<15 or ≥15 d), and source of travel health advice (company or external). Results were considered statistically significant at p < 0.05 and all analyses were performed using sas Version 9.2.
Surveys were returned by 63% (n = 383) of the 608 self-registered FBT in Rijswijk. Twenty-eight respondents did not meet the inclusion criterion of traveling to a malaria-endemic country in the preceding 2 years, and a further 27 FBT did not finish the questionnaire. Only the 328 completed questionnaires that adhered to our inclusion criteria were used for analysis.
Demographic characteristics of the study cohort are described in Table 1. The vast majority of FBT were male (n = 311; 95%) and aged between 46 and 60 years (n = 205; 63%), and the most common nationality was Dutch (n = 146; 45%). No statistical association of demographic characteristics with knowledge level was found.
Table 1. Demographic characteristics of study population
Age category (years)
Country of residence
Most FBT (n = 232; 71%) sought travel health advice before their trip. The most common reason given for not seeking advice among those who did not (n = 47; 49%) was that the FBT “knew what to do.” FBT with a longer duration of stay were more likely to consult health advice (p = 0.01). The vast majority of trips were planned less than 2 months before departure (n = 269; 82%), and almost one third (n = 89; 27%) of business travel was arranged within just 2 weeks of departure (Figure 1).
FBT who had sought company travel health advice perceived risk significantly more accurately than those seeking advice from external sources (p = 0.03). However, seeking company travel health advice was also significantly associated with an increased tendency to overestimate the risk of typhoid (odds ratio = 2.03; 95% confidence interval = 1.23–3.34). Among countries with a sufficient sample size (n ≥ 10), the most common destinations of Nigeria (n = 142) and Malaysia (n = 67) produced mean knowledge scores of 4.2 and 3.7 out of 11, respectively. FBT visiting Gabon (n = 23) scored highest, with an average of 4.7 correct responses out of 11.
The accuracy of perceived risk for each disease is presented in Figure 2. Correct responses were those agreeing with the actual disease risk. Incorrect responses were those that either overestimated or underestimated risk. On an average, underestimation of risk was 23% more common than overestimation. The majority of individuals underestimated risk for polio (52%), dengue fever (55%), cholera (57%), and influenza (67%). Just 4% of FBT underestimated risk of HIV. With the exception of HIV (overestimated by 75% of FBT), all infectious diseases were overestimated by less than half of the FBT (0% for hepatitis A and B, 1.9% for cholera, 2.4% for influenza, 4.7% for dengue fever, 4.8% for polio, 6.7% for meningitis and yellow fever, 18.7% for rabies, and 42% for typhoid fever).
It is encouraging to see that the vast majority of FBT in our study (71%) sought travel health advice despite having extensive previous travel experience. As 83% of these FBT consulted a company source of advice, we can deduce that Shell's health, safety, security, and environment (HSSE) culture is successfully encouraging health advice-seeking behavior, and that health services are sufficiently easy to access. It is important to note that employees of corporations with a less proactive health culture may have a lower uptake of health care services, so drawing parallel conclusions from our cohort of FBT may be unrealistic. For instance, higher knowledge scores demonstrated by those seeking company as opposed to external advice are likely the product of Shell's HSSE-driven strategies and frequent quality assessment of services.
Despite the high uptake of travel health services, the accuracy of the FBT's risk perception is arguably insufficient, given the frequency of their travel to high-risk regions. This is of particular consequential importance when FBT underestimate the risk of disease in their destination country, as reduced risk awareness may lead to reduced precautionary behavior. Indeed, the relationship between underestimated disease risk and compliance with vaccination advice and/or prevention measures has yet to be explored. With 92% of our cohort spending all or part of their trip in a city, assessing underestimation of diseases commonly transmitted in crowded urban areas (such as dengue fever and influenza) is particularly valuable. Influenza risk was underestimated by 67% of our FBT, reflecting previous evidence where 79% of business travelers were found not to seek pre-travel advice about influenza. As the most common travel-associated, vaccine-preventable infectious disease, it is vital to increase FBT awareness of risk distribution, prevention measures, and associated symptoms. New strains of influenza have the potential to cause outbreaks distributed via the global aviation network of travelers. Dengue fever was underestimated by 55% of our FBT, and currently has no vaccine. Frequency of diagnosis of dengue fever among travelers is increasing, and global surveillance data show dengue to exceed malaria risk for travelers to Southeast Asia and Central America, and have a higher proportionate morbidity than malaria for travelers to Thailand, Brazil, and India. Since our FBT traveled to each of these regions, the company travel health clinic must ensure that FBT are equally as informed about mosquito-borne pathogens besides malaria.
Overestimation of disease risk among FBT is likely to reflect parallel overestimation among health care professionals providing travel health advice. While overestimation of risk is favorable to underestimation, it can result in unnecessary enrolment in vaccination and chemoprophylaxis schedules. HIV, for which risk was overestimated by 75% of our FBT, has received extensive public media attention worldwide, and Shell followed suit between 2003 and 2006 by launching awareness programs in over 60 countries. We postulate that global efforts to focus detailed information on high-risk groups only would aid in dispelling disproportionate fear among those at low risk. The statistical association of typhoid risk overestimation with seeking company health advice demonstrates overexaggeration of typhoid risk specifically within Shell's travel clinic. More careful evaluation of the real typhoid risk to the traveler would allow Shell health care professionals to reduce the number of unnecessary typhoid vaccinations.
More accurate knowledge will nevertheless do little to reduce infectious disease-related morbidity if it does not lead to preventative behavior. For this, adequate time to complete required vaccination schedules is paramount, and it is therefore of concern that almost one third (27%) of trips were planned within 2 weeks of departure. There is evidence to suggest that both short-notice and business travelers tend to adopt more high-risk behavior. We cannot make conclusive statements about compliance, as preventative behavior was not measured in our survey. However, these previous findings imply that the sizeable group of Shell FBT embarking on short-notice trips may be at higher risk of acquiring disease than the rest of the cohort.
Several drawbacks to this study require attention. First, self-registration of FBT and the voluntary nature of the questionnaire may have introduced responder bias; FBT with more confidence in the accuracy of their risk perception, for instance, may have been more likely to complete the survey, thus raising knowledge scores. Second, our specific FBT definition also necessitates caution when comparing this cohort to other business travelers. Additionally, traveler risk depends as much on the individual travel profile as on trip location, so WHO country prevalence data are an imprecise proxy marker for traveler risk. The 55% FBT underestimation of polio risk, for instance, is artificially high. Wild transmission occurring within local populations of countries with poorly implemented childhood immunization programs (including the common FBT destinations of India and Nigeria) is of negligible actual risk to a vaccinated traveler. Our study would have benefited greatly from closer assessment of vaccination status, as well as trip features such as location, hygiene standards, access to health services, and FBT adherence to simple prevention measures. We can only hypothesize, based on the high level of compliance to malaria prophylaxis among the same FBT (92%), that adherence to prevention measures for other infectious diseases would also be high. The logistical obstacles of investigating these factors, however, are numerous, and explain why a sound evidence base for traveler-specific risk in relation to travel characteristics is lacking in travel medicine research.
This study sheds light on the knowledge gap that exists among these FBT. While they are well supported in terms of health advice services, their risk knowledge could certainly be improved. The most urgent intervention is required to address the underestimation of influenza and dengue fever, and to educate employees about appropriate preventative measures. The worldwide spread of the SARS virus in 2003 served to highlight that insufficient awareness among travelers can drive the global outbreak of a disease. Travel preparation should consequently be encouraged to commence earlier than seen in our data to allow for an adequate time period to complete any necessary travel preparation. With the continuing increase in both global business and leisure travel, we urge a greater evidence base for traveler-specific risk for infectious diseases to be developed, thus facilitating research that could have substantial implications for the future management of global infectious disease transmission.
No grants or other financial support were received to conduct the study. The manuscript has been seen and approved by all authors, who accept full responsibility for the content. The authors had full access to the data and their analysis, as well as drafting the article or editing an author's draft.
Declaration of Interests
The authors state that they have no conflicts of interest.
This is the entrance of the Syuanguang temple located in Sun Moon Lake area, Taiwan. This temple is famous to travelers because it enshrines a statue (and a relic) of master Xuanzang (between 596 or 602–664). He was a Chinese Buddhist monk, scholar, and traveler. He traveled throughout China but became famous for his 17-year overland journey to India (629–645) which provided the inspiration for the classical novel “Journey to the West”, written by Wu Cheng'en during the Ming Dynasty, around nine centuries after Xuanzang's death. The wall painting shows his travels and depicts him as a back-packing monk. Photo Credit: Eric Caumes (Setting: Sun Moon Lake area, Taiwan)