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Poster presentation at the 9th Conference of International Society of Travel Medicine, Lisbon, May 1 to 5, 2005, and also at the 8th Conference of International Society of Travel Medicine, New York, May, 2003.
Nicholas Zwar, MBBS, Travel Health Advisory Group, PO Box A1172, Sydney South, NSW 1235, Australia. E-mail: email@example.com
Background More Australians are traveling to overseas destinations where preventable infectious diseases, such as hepatitis A, are endemic. Yet, there is only limited data concerning the extent to which Australians seek travel advice and vaccination before their departures.
Method Annual telephone surveys were conducted among adult Australians travelers. Information was collected on the travel advice and vaccinations received before departure. Perceptions about, and their potential exposure to, travel-related infections while overseas were also assessed. This paper presents data from the 2003 survey related to travel advice and hepatitis A, while hepatitis B is discussed in the companion article.
Results Only a third of interviewees had sought health advice before travel. Infrequent travelers, those departing for endemic countries or for longer journeys, were more likely to seek medical advice. Overall, 32% of interviewees had been vaccinated against hepatitis A, with travelers to high/medium–hepatitis A endemicity destinations being more likely to be vaccinated than those visiting low-endemicity countries (44% vs 20%). Among the 263 visitors to endemic countries, those who stayed with friends and relatives were least likely to be vaccinated against hepatitis A compared to other styles of accommodation.
Conclusions Despite government recommendations and industry group campaigns about the need for pretravel advice, the majority of Australians travel overseas without adequate health advice and protection against hepatitis A and other travel-related infectious diseases.
In 2004, there were 4.4 million short-term resident departures from Australia and the number traveling overseas continues to grow.1 Although most short-term departures are to New Zealand and the UK, the fastest growing destinations for Australian travelers are in Southeast Asia where the risk for infectious diseases such as hepatitis A and hepatitis B are substantially higher than in Australia.
Although estimates of risk have declined in the past 20 years, hepatitis A remains a common vaccine-preventable disease among travelers.2–7 Australia, like many developed countries, has a low-endemicity pattern for hepatitis A, and because of lack of exposure in childhood, many adult Australians are at risk for hepatitis A infection when traveling to regions of higher endemicity.8 Backpackers who travel for prolonged periods in poor hygienic conditions and travelers who visit friends and relatives are likely to be at particular risk.3–7 Though one means of protection is strict food and drink hygiene, travelers generally are not able to consistently follow the advice “boil it, cook it, peel it or leave it.” Within the first 3 days of their stay abroad, 98% of Swiss travelers reported a breach in food or drink hygiene standards.9
Notwithstanding the frequency of travel, there is little information available on the extent to which Australian travelers seek pretravel health advice, what vaccinations they receive, and what risks they are exposed to during travel. A series of surveys of Australian travelers examining these questions was conducted under the auspices of the Travel Health Advisory Group, a coalition of Australian travel and medical organizations. This paper presents the results of these surveys focusing on the extent to which Australian travelers seek pretravel health advice and immunization for hepatitis A, as well as their risk of hepatitis A exposure during travel. The accompanying paper by Streeton and Zwar examines the risks and preventive behaviors for blood-borne infection, in particular hepatitis B.10
Over the period 2001 to 2003, a series of three annual telephone surveys was conducted in a random selection of urban Australians aged 18 years and older who had traveled overseas for business or pleasure within the previous 2 years. On each occasion, a market research company telephoned people from Australian mainland capital cities (Sydney, Melbourne, Brisbane, Perth, and Adelaide) using lists of telephone numbers generated at random from the residential telephone directory. Up to three telephone calls were made to numbers that were not answered. Eligible respondents were identified using screening questions regarding overseas travel in the past 2 years and their age and then asked to participate in the survey. This process continued until at least 500 people had been interviewed using a structured questionnaire. Interviews were conducted mostly between 4 p.m. and 9 p.m. on a daily basis over a 3-week period.
A mixture of open and multiple-choice questions was asked about their destination(s), style of accommodation, reasons for travel and frequency, and duration of travel. They were also asked about what, if any, health advice had been sought and received before travel, and what travel vaccinations they had received. Questions were asked to determine the interviewee’s level of understanding of hepatitis A and vaccination. In addition, interviewees were informed how hepatitis A was contracted and then asked if they believed they might have been exposed to these infections on their most recent trip.
Data are presented as percentages of the sample as a whole, or of the subsets of interest within the sample. The chi-square test was used to assess the significance of any differences between groups. The endemicity of countries visited by the interviewees were classified according to the US Center for Disease Control and Prevention’s geographic distribution data for hepatitis A prevalence, 2000.11
The data collected in three annual surveys were consistent in terms of the demographics, destinations and duration of travel, and the rates of pretravel advice and vaccination. Table 1 summarizes the demographics for the samples over the 3 years. Over that time, there was little change in travelers’ knowledge or behavior while traveling. Because the more recent data are the most relevant and there were some differences in the wording of the questions asked, the results focus on information from the 2003 survey.
Table 1. Travelers and their destinations in the previous 2 years in three annual surveys 2001–2003
Destinations for the cohort of 503 adults in the previous 2 years were Asia (40%), Northern Europe (34%), Southern Europe (13%), North America (16%), Oceania including New Zealand (19%), Eastern Europe (3%), Africa (4%), Middle East (2%), South America (2%), and Central America (1%), with some having more than one destination.
As defined by the US Center for Disease Control and Prevention, 2000.
In the search for eligible respondents, 9,634 telephone calls were made to contact 4,203 people. Screening questions excluded 83.8% of those contacted as ineligible for the study. Of the 679 eligible respondents, 503 (74%) completed the interview.
Only 168 or 33% of 503 travelers visited a doctor (29%) or travel health clinic (4%) prior to their last overseas trip—the majority (68%) within 5 weeks of travel. Approximately a third left their consultation until 2 or fewer weeks before departure. The traveler’s age, gender, and socioeconomic status did not affect the propensity to seek medical advice. However, destination, duration of the trip, and frequency of travel during the past 2 years did appear to have an effect. Travelers to high/medium–hepatitis A and/or hepatitis B endemicity countries were more likely to seek professional advice (131/316, 41%) than travelers to only low-endemicity countries (37/187; 20%); p < 0.0001 (χ2= 23.8, df = 1 Yates corrected), while those embarking on longer trips were more likely than those taking short trips to seek advice: 46% (32/70) before a long trip (>3 months), and 32% (44/136) and 21% (62/297) before a medium (1–3 months) and short trip (<1 month), respectively; p < 0.001(χ2= 19.8, df = 2). Interviewees who were frequent travelers (two or more trips in the past 2 years) were less likely to have seen a doctor before the last trip (50/206; 24%) than infrequent travelers (116/295; 39%); p = 0.0006 (χ2= 11.7, df = 1 Yates corrected).
Cited reasons (n = 312) for not seeing a doctor before their last trip were most commonly related to a perceived lack of risk in the destination(s), for example, “traveling to a safe country” (34%), “previous uneventful travel to the destination” (17%), “no need” (14%), “advised by friends or others it was safe” (8%), “country of origin or staying with family” (10%) and “didn’t think about it” (2%). For approximately half of those not seeking advice (185/335, 55%,), their destination(s) had medium/high risk for hepatitis A and/or hepatitis B. “Being up-to-date with vaccinations” was cited as reason for not visiting a doctor by only 13% of interviewees.
Interestingly, only about half (48%) of those consulting a doctor before their last trip (n = 168) recalled being advised to vaccinate regardless of whether or not they were traveling to a medium/high-risk destination. Of those individuals traveling to a medium/high-risk destination who were advised not to vaccinate (n = 56), 46% recalled being told that vaccination was not needed because the destination was a “safe country or low risk” and another 11% were told there was no need.
Hepatitis A risk
Approximately half or 263 interviewees had traveled to destinations(s) with a high (40%) or medium (12%) risk for hepatitis A. A younger traveler was no more likely to visit a high/medium-endemic country than an older traveler. Despite a decline in overseas travel during 2003 due to world events, Asian countries were the most popular destination for travelers in the survey, with 40% or 201 traveling to at least one Asian country during the previous 2 years. Of the 263 travelers to hepatitis A–endemic countries, 59% stayed in five, four, or three star hotels, while 27% visited/stayed with friends and relatives. The remainder stayed in budget accommodation (Figure 1).
Hepatitis A vaccination status
Overall, 163 (32%) of those interviewed (n = 503) reported being vaccinated against hepatitis A, either for their last trip (n = 37) or on a previous occasion (n = 126). People traveling to high/medium–hepatitis A endemicity destinations were more likely to be vaccinated against hepatitis A compared to those traveling to low-risk countries; 92/201 (46%), 24/62 (39%), and 47/240 (20%) of travelers to high-, medium-, and low-endemicity countries, respectively, were vaccinated; p < 0.001 (χ2= 35.5, df = 2). As shown in Figure 1, among the 263 travelers to high/medium–hepatitis A risk countries, those staying mainly with friends and relatives were less likely to be vaccinated against hepatitis A (30%; 21/71) than those using other styles of accommodation (48%; 93/192); p < 0.05 (χ2= 9.1, df = 3).
Approximately 30% or 150 interviewees (n = 503) could recall a situation in which they may have been exposed to the risk of a food-borne infectious disease during their last overseas trip, and of these, 60% were unvaccinated against hepatitis A. Of 90 interviewees who could both recall a risk exposure and were unvaccinated, 55 (60%) had visited a high/medium-risk hepatitis A destination.
Perceptions of hepatitis A
Approximately a third or 181 interviewees (n = 503) did not know how hepatitis A was contracted, and 75 (15%) nominated hepatitis A as the most commonly caught travel disease. In comparison, 176 (35%) nominated malaria and 30 (6%) nominated typhoid fever as the most common travel-related infectious disease. Moreover, more interviewees were spontaneously aware of the availability of typhoid vaccine (161 or 32%) than of hepatitis A vaccine (101 or 22%).
A minority of interviewees (33%) reported seeing a doctor or travel clinic for pretravel health advice and of those who did seek advice, a third did so within 2 weeks of departure. The rate of seeking professional advice remained low across the years of the survey, despite the growing trend for Australians to travel to countries with high or medium endemicity for infectious diseases1 and the advice of Australian government and industry groups about the potential health risks of overseas travel.8 However, Australians are not unique in this regard. Airport surveys conducted in Europe and the United States suggest that less than half of European travelers,12 and only a third of Americans seek pretravel health advice from a doctor or travel medicine clinic.13 Moreover, in an airport survey conducted in one Australian and four Southeast Asian airports, Asian travelers were less likely to seek advice than travelers from Australia, New Zealand, Europe, and North America.14 While it was somewhat reassuring that those in the survey who traveled to endemic countries or embarked on longer trips were more inclined to seek medical advice, the numbers are still low. Familiarity with travel and an often erroneous perception of the health risks in overseas countries tended to dissuade people from seeking advice.
The low level of vaccination against hepatitis A among Australian travelers is of particular concern given that overseas travel is the most commonly reported risk factor for notified case of hepatitis A infection in Australia. In 2003, among 101 cases of hepatitis A infection where risk factors were identified (24% of all notifications), overseas travel was a factor for 51% of infections.15 High rates of imported hepatitis have been observed in other low-endemicity areas of the world where residents travel frequently to high-endemicity countries. For instance, in Quebec and Ontario in Canada, Italy, and Switzerland an estimated 33, 28 and 42%, respectively, of reported cases of hepatitis A were considered travel related.7,16,17 De Serres and colleagues16 suggested that current strategies for prevention of hepatitis A in travelers, such as recommendations to vaccinate those traveling to endemic countries, are relatively ineffective due to the low uptake of vaccination, and that other strategies need to be considered. Attitudes among doctors may also be a barrier to vaccination because almost half of those who did present for pretravel health advice and who were traveling to a medium- or high-risk destination recalled being told that hepatitis A vaccination was not needed.
A number of studies have identified travelers (especially children) who visited friends and relatives in endemic countries as a major source of imported hepatitis A infection.18–22 Although the current survey only included adults, the significantly lower rate of vaccination among those who visited friends and relatives (30% compared to 48% for other forms of accommodation) in high/moderate-endemicity countries suggests that this group of travelers needs to be especially targeted for hepatitis A vaccination.
As with all surveys, the study results have a number of limitations including the potential for sampling bias related to telephone ownership and unlisted numbers, and the risk of positive respondent bias due to the voluntary nature of the interviews. Of note is the high female to male ratio across the years, which is typical of surveys that randomly seek an adult respondent for a phone interview. However, the sample showed some consistency with the Australian Bureau of Statistics’ (ABS) resident departure data for 2003. The duration of travel reported by respondents in the survey was similar to that recorded in the ABS data, and the survey’s destination data were similar but not entirely comparable to the ABS data because the latter records the main destination for overseas departures in the previous year, rather than all destinations in the previous 2 years, as in the survey.1,23 The information obtained in the survey was also subject to recall bias and there is an assumption that an individual reporting vaccination is adequately immunized, which is not necessarily the case, if the vaccination schedule was incomplete.
Notwithstanding these unavoidable shortcomings, the survey results indicate there are substantial numbers of travelers who are not seeking pretravel health advice and who are at risk of hepatitis A during travel. Despite campaigns supported by the Travel Health Advisory Group to raise awareness of the risk of hepatitis A, the survey suggests there has been little change in the behavior of Australian travelers and perhaps there is a need for greater and more effective public education about the importance of pretravel health advice and appropriate vaccination. Further research is needed into the knowledge and attitudes of travelers and the barriers to seeking pretravel professional health advice and vaccination. This research would inform the development of strategies to encourage appropriate uptake of professional pretravel health advice. Possible strategies include more effective work with the travel industry and health professionals in raising the profile of pretravel health advice and vaccination and also more promotion by government, such as through the Australian Government travel information Web site. Other strategies include targeting of high-risk groups, such as those visiting friends and relatives and the development of a whole-of-life vaccination record to assist individuals and their health providers to accurately assess vaccination status.
Travel Health Advisory Group (THAG) member organizations are the Australian Federation of Travel Agents (Ms Marie Allom); MASTA—Minding Your Health Abroad (Dr Bernard Hudson); Royal Australian College of General Practitioners (Professor Nicholas Zwar); School of Public Health and Tropical Medicine, James Cook University (Associate Professor Peter Leggat), Rede-Health International (Dr Bob Kass), Qantas Airways (Ms Bronwyn Claxton); and Youth Hostels Association Australia (Mr Ben Fryer). Funding from GlaxoSmithKline Australia Ltd supports THAG activities. Statistical assistance with data analysis was provided by Mr Stephen Linz, GSK Australia.
Declaration of interests
The survey was carried out under the auspices of the Travel Health Advisory Group (THAG). GlaxoSmithKline provides financial support for various activities of THAG including the survey. C. L. S. is an employee of GlaxoSmithKline. N. Z. is a member of THAG and has acted as a consult to GlaxoSmithKline in an unrelated field to travel medicine. He has received travel grants from GlaxoSmithKline and Pfizer.