Risks of hepatitis B in travelers as compared to immunization status

Acceptance of yellow fever vaccine in the older traveller: a cohort study

BACKGROUND AND AIM

Current demographic changes and improvement of quality of life of elderly population have direct consequences on international travelling. The older traveller demands for specific care and precautions to be observed, as for the yellow fever (YF) vaccination, due to the increased incidence rate of adverse events following immunization (AEFI) in people aged 60 years or over. The aim of our study was to determine the adherence to YF vaccine and travel behaviours in a sample of elderly travellers moving to YF endemic areas.

METHODS

Participants in this cohort study were offered YF vaccine, and informed about the increased risk of AEFIs and the unavoidable risk of acquiring YF at the destination. The research was planned on survey-based design, using pre- and post-travel questionnaires.

RESULTS

In 2018, 239 travellers aged 60 years or older attended our travel clinic, of whom 36.8% (n = 88) planned to travel to YF endemic areas and 23.0% (n = 55) for the first time. Of these, 63.6% accepted and 36.4% rejected the vaccination, with 15 travellers moving to endemic areas without immunization, including one patient who presented contraindications to YF vaccine.

CONCLUSIONS

The presence of more than a third of elderly travellers who travelled without vaccination is a substantial public health problem and, since the number of older travellers continues to increase, it becomes necessary to implement robust actions to improve YF vaccine advocacy and adherence.

Vaccines and Senior Travellers

Background: International tourist travel has been increasingly steadily in recent years, and looks set to reach unprecedented levels in the coming decades. Among these travellers, an increasing proportion is aged over 60 years, and is healthy and wealthy enough to be able to travel. However, senior travellers have specific risks linked to their age, health and travel patterns, as compared to their younger counterparts. Methods: We review here the risk of major vaccine-preventable travel-associated infectious diseases, and forms and efficacy of vaccination for these diseases. Results: Routine vaccinations are recommended for older persons, regardless of whether they travel or not (e.g., influenza, pneumococcal vaccines). Older individuals should be advised about the vaccines that are recommended for their age group in the framework of the national vaccination schedule. Travel-specific vaccines must be discussed in detail on a case-by-case basis, and the risk associated with the vaccine should be carefully weighed against the risk of contracting the disease during travel. Travel-specific vaccines reviewed here include yellow fever, hepatitis, meningococcal meningitis, typhoid fever, cholera, poliomyelitis, rabies, Japanese encephalitis, tick-borne encephalitis and dengue. Conclusion: The number of older people who have the good health and financial resources to travel is rising dramatically. Older travellers should be advised appropriately about routine and travel-specific vaccines, taking into account the destination, duration and purpose of the trip, the activities planned, the type of accommodation, as well as patient-specific characteristics, such as health status and current medications.

HIV, Other Blood-Borne Viruses and Sexually Transmitted Infections amongst Expatriates and Travellers to Low- and Middle-Income Countries: A Systematic Review

In some high-income countries, a proportion of human immunodeficiency virus (HIV), other blood-borne virus (BBV) or sexually transmitted infection (STI) diagnoses have been reported as acquired overseas in low- and middle-income countries. A review was conducted to explore HIV, other BBV or STI related knowledge, risk behavior and acquisition amongst expatriates and travelers, particularly males, travelling from high to low- and middle-income countries. Seven academic databases were searched for 26 peer reviewed articles that met inclusion criteria. Significant variability in the studies was noted, in age, travel duration and frequency and outcomes/risk factors measured and reported on. Risk factors described included longer duration of stay; being single; travel for romance or sex; alcohol and other drug use; lack of travel advice; being male; higher number of sexual partners; and inconsistent condom use. Vaccination, pre-travel health advice, and having fewer sexual partners were described as protective. Studies are needed focusing on the social context in which risk-taking occurs. Better collaboration is essential to deliver comprehensive health promotion interventions alongside more consistent pre- and post- travel testing and advice. Policy measures are crucial, including consistent evaluation indicators to assess impacts of HIV, other BBVs or STIs in the context of mobility. Risks and responses for these epidemics are shared globally.

Hepatitis B: A cross-sectional survey of knowledge, attitudes and practices amongst backpackers in Thailand

BACKGROUND

In 2013, 200 million tourists visited countries that are endemic for hepatitis B virus (HBV). Backpackers are potentially at greater risk of hepatitis B than other travellers yet exposure to HBV remains under researched in this population.

METHOD

A cross-sectional survey of backpackers visiting two islands in Thailand was performed during early 2015. Participation in activities with high HBV exposure risk was recorded, alongside rates of vaccination and an evaluation of knowledge and attitudes towards the risk of HBV.

RESULTS

1680 questionnaires were completed and analysed; the median participant age was 24 (range: 18-68) and 47.9% were male. 20.8% took part in activities with a high risk of HBV exposure. Over two-thirds of the sample were not protected against HBV. 24% were able to correctly identify HBV transmission methods. 44.1% underestimated the risk of HBV in Thailand.

CONCLUSIONS

The proportion of backpackers participating in high-risk activities was double the level found in previous studies that have examined the HBV exposure risk amongst travellers to endemic countries. Voluntary risk activities were the largest source of potential exposure to HBV and rates of vaccination are low. Backpackers should be considered for routine vaccination and education on risk behaviours should be included in the pre-travel consultation.

Hepatitis B vaccination for international travelers to Asia

There is a wide range in prevalence of hepatitis B virus (HBV) infection and HBV immunization programs between different regions. Hepatitis B is a vaccine preventable disease yet is still endemic in the majority of countries in Asia. Despite the decreasing global prevalence of chronic HBV infection, there is still considerable risk of HBV infection among international travelers to high endemic areas. Numbers of international travelers are expected to increase year by year; thus immunization among this cohort is a crucial preventive measure. Among international travelers to Asia, HBV immunization should be recommended for those without previous HBV vaccination who plan to travel to countries with intermediate to high prevalence of HBV, and especially for those individuals at greater risk of HBV infection; including travelers engaging in casual sex, getting a tattoo or piercing, and those having dental surgery or other medical procedures. Longer duration of travel is also associated with a greater risk of HBV infection. Travelers from low HBV prevalence countries, especially those born before implementation of universal HBV vaccination, might benefit from HBV vaccination during long-term traveling to HBV intermediate to high endemic country.

Pre-travel advice, attitudes and hepatitis A and B vaccination rates among travellers from seven countries†

BACKGROUND

Knowledge about the travel-associated risks of hepatitis A and B, and the extent of pre-travel health-advice being sought may vary between countries.

METHODS

An online survey was undertaken to assess the awareness, advice-seeking behaviour, rates of vaccination against hepatitis A and B and adherence rates in Australia, Finland, Germany, Norway, Sweden, the UK and Canada between August and October 2014. Individuals aged 18-65 years were screened for eligibility based on: travel to hepatitis A and B endemic countries within the past 3 years, awareness of hepatitis A, and/or combined hepatitis A&B vaccines; awareness of their self-reported vaccination status and if vaccinated, vaccination within the last 3 years. Awareness and receipt of the vaccines, sources of advice, reasons for non-vaccination, adherence to recommended doses and the value of immunization reminders were analysed.

RESULTS

Of 27 386 screened travellers, 19 817 (72%) were aware of monovalent hepatitis A or combined A&B vaccines. Of these 13 857 (70%) had sought advice from a healthcare provider (HCP) regarding combined hepatitis A&B or monovalent hepatitis A vaccination, and 9328 (67%) were vaccinated. Of 5225 individuals eligible for the main survey (recently vaccinated = 3576; unvaccinated = 1649), 27% (841/3111) and 37% (174/465) of vaccinated travellers had adhered to the 3-dose combined hepatitis A&B or 2-dose monovalent hepatitis A vaccination schedules, respectively. Of travellers partially vaccinated against combined hepatitis A&B or hepatitis A, 84% and 61%, respectively, believed that they had received the recommended number of doses.

CONCLUSIONS

HCPs remain the main source of pre-travel health advice. The majority of travellers who received monovalent hepatitis A or combined hepatitis A&B vaccines did not complete the recommended course. These findings highlight the need for further training of HCPs and the provision of reminder services to improve traveller awareness and adherence to vaccination schedules.

HAV & HBV vaccination among travellers participating in the National Health and Wellness Survey in five European countries

BACKGROUND

A main cause of hepatitis A and B infections in European countries is travel to endemic countries. Most research on hepatitis vaccination among travellers from Europe has been conducted in airports or travel clinics, samples which potentially overrepresented frequent travellers.

METHODS

2102 respondents across France, Germany, Italy, Spain, and UK completed an internet-based questionnaire. Vaccination status, travel to endemic countries, and other characteristics were compared across frequent, occasional, and non-travellers. Logistic regressions tested association between vaccination and travel adjusting for potential confounders.

RESULTS

Most respondents were occasional travellers (61%) and 24% were frequent travellers. Frequent travellers had 2.3-2.4 times the odds of being vaccinated relative to non-travellers, and odds of vaccination were 2.5-3.1 times higher among travellers to endemic areas relative to others (all p < .05). Frequent travellers were more aware of their vaccination status (HAV: 80% vs. 72%; HBV: 82% vs. 74%), though many who were vaccinated could not identify the number of injections to complete the series (47% vs. 29%) (all p < .05).

CONCLUSION

Travel frequency and destination endemicity are associated with increased hepatitis A and B vaccination. The number of unvaccinated travellers and the lack of recall for the dosing schedule suggest the need to improve travellers' awareness and adherence to recommendations.

Travel-acquired infections in Canada: CanTravNet 2011-2012

BACKGROUND

Important gaps remain in our knowledge of the infectious diseases people acquire while travelling and the impact of pathogens imported by Canadian travellers.

OBJECTIVE

To provide a surveillance update of illness in a cohort of returned Canadian travellers and new immigrants.

METHODS

Data on returning Canadian travellers and new immigrants presenting to a CanTravNet site between September 2011 and September 2012 were extracted and analyzed by destination, presenting symptoms, common and emerging infectious diseases and disease severity.

RESULTS

During the study period, 2283 travellers and immigrants presented to a CanTravNet site, 88% (N=2004) of whom were assigned a travel-related diagnosis. Top three destinations for non-immigrant travellers were India (N=132), Mexico (N=103) and Cuba (N=89). Fifty-one cases of malaria were imported by ill returned travellers during the study period, 60% (N=30) of which were Plasmodium falciparum infections. Individuals travelling to visit friends and relatives accounted for 83% of enteric fever cases (15/18) and 41% of malaria cases (21/51). The requirement for inpatient management was over-represented among those with malaria compared to those without malaria (25% versus 2.8%; p<0.0001) and those travelling to visit friends and relatives versus those travelling for other reasons (12.1% versus 2.4%; p<0.0001). Nine new cases of HIV were diagnosed among the cohort, as well as one case of acute hepatitis B. Emerging infections among travellers included hepatitis E virus (N=6), chikungunya fever (N=4) and cutaneous leishmaniasis (N=16). Common chief complaints included gastrointestinal (N=804), dermatologic (N=440) and fever (N=287). Common specific causes of chief complaint of fever in the cohort were malaria (N=47/51 total cases), dengue fever (14/18 total cases), enteric fever (14/17 total cases) and influenza and influenza-like illness (15/21 total cases). Animal bites were the tenth most common diagnosis among tourist travellers.

INTERPRETATION

Our analysis of surveillance data on ill returned Canadian travellers provides a recent update to the spectrum of imported illness among travelling Canadians. Preventable travel-acquired illnesses and injuries in the cohort include malaria, enteric fever, HIV, hepatitis B, hepatitis A, influenza and animal bites. Strategies to improve uptake of preventive interventions such as malaria chemoprophylaxis, immunizations and arthropod/animal avoidance may be warranted.

Summary of recommendations for the prevention of viral hepatitis during travel

Viral hepatitis is considered the most common travel-related, vaccine-preventable disease. All non-immune travellers to developing countries should consider vaccination with inactivated Hepatitis A (HA) virus vaccine and recombinant Hepatitis B (HB) virus vaccine. Inactivated HA and recombinant HB vaccines are safe, have few side effects and are effective in providing long-lasting protection. All monovalent HA and HB vaccines available for use within Canada are equally effective, and each can be used interchangeably. HA Ig (immune globulin) should be used to prevent HA only in those for whom active HA vaccines are contraindicated, in immunocompromised individuals who may not respond adequately to the active vaccines or in infants less than one year of age. All travellers should practise routine protective measures when abroad. HB virus carriers travelling to Hepatitis D virus-endemic countries should be particularly vigilant in avoiding high-risk activities such as skin piercing and unsafe sexual practices.

High non-responsiveness of males and the elderly to standard hepatitis B vaccination among a large cohort of healthy employees

BACKGROUND

Hepatitis B virus infection is a major health problem. Although non-response is known to increase with age, hepatitis B vaccinations are considered to have only minor non-response rates (anti-HBs<10IU/L) in healthy subjects.

OBJECTIVES

The aim of this study was to quantify immunosenescence in a large retrospective cohort of 11,439 healthy adults who received HBV immunisation according to the standard vaccination regime.

STUDY DESIGN

We evaluated the response to the standard three-dose vaccination regimen, consisting of 20-μg doses of the HbsAg recombinant DNA hepatitis B vaccine, among 11,439 healthy employees using a retrospective cohort design. Logistic regression was applied to predict the non-response rate, and multivariate regression analysis was applied to predict antibody response. Predictors of responsiveness included sex, age and time between the last vaccination and antibody titre measurement.

RESULTS

From the age of 29 on in men and 43 on in women, more than 5% of subjects did not respond. Compared with women, men had a higher risk of non-response and exhibited a steeper decline in antibody titres produced with increasing age.

CONCLUSIONS

This retrospective cohort study demonstrates that immunosenescence starts at young age, especially among men, underlining the importance of vaccination at a young age to achieve long-lasting immunity. Moreover, HBV vaccination should always include testing for antibodies to facilitate the performance of necessary interventions to prevent long-term fatal complications.

Hepatitis B and C infection in international travelers

BACKGROUND

Hepatitis B and C virus (HBV and HCV) cause significant morbidity and mortality worldwide. With the rise in international travel over the last three decades, many travelers are at risk of HBV and HCV infection.

METHODS

This review focuses on the epidemiology of HBV and HCV in international travelers, the modes of transmission, and the prevention of infection in travelers.

RESULTS

The risk of HBV and HCV infection varies widely and depends on the prevalence of the destination country, the duration of travel, and the activities undertaken while abroad. Travelers commonly undertake high-risk activities that place them at risk of both HBV and HCV infection. Poor uptake of preventative health measures and poor adherence to health recommendations are also common. The monthly incidence of HBV infection for long-term travelers to endemic countries ranges from 25 to 420 per 100,000 travelers. HBV infection can be prevented through timely vaccination of travelers. HBV vaccination is safe and efficacious with protective levels of antibodies achieved in >90% of recipients. Information regarding the risk of HCV acquisition is scarce and until recently was limited to case reports following medical interventions.

CONCLUSIONS

This review demonstrates international travelers are at risk of HBV and HCV infection and provides evidence-based information enabling health practitioners to provide more appropriate pre-travel advice. HBV vaccination should be considered in all travelers to countries with a moderate to high HBV prevalence (HBsAg ≥ 2%) and the risk and benefits discussed with the individuals in consultation with the health practitioner. There is no duration of travel without risk of HBV infection. However, it is apparent that those travelers with a longer duration of travel are at greatest risk of HBV infection (ie, expatriates). Travelers should also receive advice regarding the modes of transmission and the activities that place them at risk of both HBV and HCV infection.

The incidence of HBV and HCV infection in Australian travelers to Asia

We analyzed paired pre- and post-travel sera in a cohort of Australian travelers to Asia and demonstrated the acquisition of hepatitis C virus (HCV) and hepatitis B virus (HBV) infection. The incidence density in nonimmune travelers for HCV infection was calculated as 1.8 infections per 10,000 traveler-days and for HBV infection 2.19 per 10,000 traveler-days.

Online survey: knowledge about risks, prevention and consequences of infections with HBV among travellers from four European countries

OBJECTIVE

To evaluate knowledge about risks, prevention and consequences of infection with hepatitis B virus (HBV) among travellers from four low HBV risk, European countries.

METHODS

Individuals from an internet panel and based in the Czech Republic, the Netherlands, Spain and Sweden were invited to take part in an online survey. A total of 4203 respondents met the inclusion criteria and completed the survey.

RESULTS

The majority (62.3%) of respondents did not know the main travel destinations with moderate or high prevalence for HBV. Also, 20.1% were somewhat or very unaware of the ways in which HBV can be caught and travellers aged 18-35 years were significantly more likely (p < 0.01) to have participated in at least one risky activity abroad. Three-quarters (74.9%) thought they were somewhat or very aware of the health implications of contracting HBV, but only 11.8% of participants selected more than three out of the six correct answers relating to conditions caused by HBV. Only 39.3% of those who knew their vaccination status had received vaccination against HBV within the previous 5 years, although some patients may have been vaccinated prior to this period.

CONCLUSIONS

As country-specific variables were not analysed in this study, the results do not allow interpretation by country. A high proportion of the respondents were at an elevated risk of HBV infection while visiting moderate or high prevalence countries. They were unlikely to be immunised or take appropriate precautions; participation in risk activities abroad was high, and knowledge of HBV was limited. These findings indicate there is a need for healthcare professionals and the travel industry to educate travellers on the risks of HBV infections while abroad and the importance of preventing infection through vaccination.

Vaccine preventable diseases in returned international travelers: results from the GeoSentinel Surveillance Network

Vaccine preventable diseases (VPDs) threaten international travelers, but little is known about their epidemiology in this group. We analyzed records of 37,542 ill returned travelers entered into the GeoSentinel Surveillance Network database. Among 580 (1.5%) with VPDs, common diagnoses included enteric fever (n=276), acute viral hepatitis (n=148), and influenza (n=70). Factors associated with S. typhi included VFR travel (p<0.016) to South Central Asia (p<0.001). Business travel was associated with influenza (p<0.001), and longer travel with hepatitis A virus (p=0.02). 29% of those with VPDs had pre-travel consultations. At least 55% of those with VPDs were managed as inpatients, compared to 9.5% of those with non-VPDs. Three deaths occurred; one each due to pneumococcal meningitis, S. typhi, and rabies. VPDs are significant contributors to morbidity and potential mortality in travelers. High rates of hospitalization make them an attractive target for pre-travel intervention.

Risk of hepatitis B for travelers: is vaccination for all travelers really necessary?

OBJECTIVES

Behavioral studies in travelers suggest that 33% to 76% of all travelers to hepatitis B virus (HBV)-endemic countries are at risk for HBV infection. We study the incidence and risk factors for HBV infection in travelers.

METHODS

Retrospective analysis of the characteristics and risk factors of all reported acute HBV patients in Amsterdam, the Netherlands, from January 1, 1992, until December 31, 2003.

RESULTS

The estimated incidence in travelers from Amsterdam to HBV-endemic countries is 4.5/100,000 travelers. Two thirds of these patients were immigrants who lived in Amsterdam and who had visited their friends and relatives in their country of origin. In 12 years, only three Dutch short-term tourists contracted HBV while traveling, all by heterosexual contacts.

CONCLUSIONS

Dutch tourists who travel to HBV-endemic countries run a very low risk of contracting HBV. Vaccination of short-term Dutch tourists is not necessary. Immigrants run a higher risk irrespective of travel or duration of travel. This group should be advised vaccination.

The role of the traveler in emerging infections and magnitude of travel

Travel and trade have grown immensely. Travelers interact with people and microbes during their journeys, and can introduce infectious agents to new areas and populations. Studying illnesses in travelers is a source of knowledge into diseases of resource-poor regions and the control of these diseases. Travel-associated illnesses also serve to detect emerging infections.

Perceived vaccination status in ecotourists and risks of anthropozoonoses

Anthropozoonotic (human to nonhuman animal) transmission of infectious disease poses a significant threat to wildlife. A large proportion of travelers to tropical regions are not protected against vaccine-preventable illnesses, and a majority of these travelers demonstrate poor recall of actual vaccination status. Here we characterize self-perceived vaccination status among a large sample of ecotourists at the Sepilok Orangutan Rehabilitation Centre, Sabah, Malaysia. Despite their recognized travel itinerary to view endangered animals, tourists at wildlife sanctuaries are not adequately protected against vaccine-preventable illnesses. Of 633 surveys, over half reported being currently vaccinated against tuberculosis, hepatitis A, hepatitis B, polio, and measles. Fewer participants reported current vaccination status for influenza, rabies, and chickenpox. Despite the fact that the majority of visitors to Sepilok are from temperate regions where influenza is relatively more prevalent, 67.1% of those surveyed with medical-related occupations reported not being currently vaccinated for influenza. Ecotourists concerned about environmental protection are themselves largely unaware of their potential contribution to the spread of diseases to animals. The risks of negatively affecting animal populations must be communicated to all concerned parties, and this may begin by urging travelers to examine their actual vaccination status, particularly as the ecotourism industry continues its rapid expansion, and is seen increasingly as a possible tool to save great ape populations from extinction.

The underestimated risk of hepatitis A and hepatitis B: benefits of an accelerated vaccination schedule

Hepatitis A virus (HAV) and hepatitis B virus (HBV) are vaccine-preventable. Current recommendations advocate vaccination of non-immune adults at risk of exposure, including travelers to HAV or HBV endemic areas, individuals with high risk of contracting a sexually transmitted infection, and some correctional facility inmates. We review the use of an accelerated schedule to administer the combination hepatitis A and hepatitis B vaccine (Twinrix). Administering three doses over three weeks and a fourth at 12 months provides rapid initial protection of most individuals for whom the standard 6-month vaccination schedule would not be suitable, including last-minute travelers and short-term correctional facility inmates. Furthermore, we consider the role of a universal vaccination strategy in preventing the spread of HAV and HBV.

Sexual health and HIV in travellers and expatriates

Travellers engaging in sexual contact with a new partner abroad may be at high risk of acquiring a sexually transmitted infection. This review examines the impact of travel on sexual health and provides prevention, management and treatment recommendations to practising occupational health physicians.

Should hepatitis B vaccination be introduced into childhood immunisation programmes in northern Europe?

Infection with hepatitis B causes between 500,000 and 1.2 million deaths per year worldwide, and is the leading cause of liver cancer. Over 12 years ago, WHO recommended that universal childhood hepatitis B vaccination be implemented globally. Despite this, Denmark, Finland, Iceland, Ireland, the Netherlands, Norway, Sweden, and the UK have yet to implement such a policy and instead currently adopt an "at-risk" strategy. Although all eight countries are classed as having low endemicity, factors such as increased travel and integration of immigrant communities are increasing the number of at-risk individuals in these countries. Considering the difficulty in identifying all at-risk individuals, and the lack of effectiveness of at-risk vaccination on reducing the overall incidence of hepatitis B, we recommend that these countries reassess their hepatitis B prevention strategies. Universal vaccination against hepatitis B is the only way to eliminate the major public-health impact of this disease.

Rapid and sustained immune response against hepatitis A and B achieved with combined vaccine using an accelerated administration schedule

BACKGROUND

Combined hepatitis A and B vaccine administered on an accelerated schedule provides a rapid immune response against both hepatitis A and B viruses, which might be especially relevant for individuals who need protection quickly.

METHODS

A prospective, open-label, randomized study to compare the immunogenicity and reactogenicity of the combined hepatitis A and B vaccine Twinrix (GlaxoSmithKline Biologicals, Rixensart, Belgium) (>or=720 EL.U/mL inactivated hepatitis A antigen and 20 microg/mL recombinant hepatitis B surface antigen [HBsAg]) administered at 0, 7, 21 to 30 days, and 12 months compared with concurrent administration of Havrix [GlaxoSmithKline Biologicals, Rixensart, Belgium (>or=1440 EL.U/mL inactivated hepatitis A antigen)] at 0 and 12 months, and Engerix-B [GlaxoSmithKline Biologicals, Rixensart, Belgium (20 microg/mL recombinant HBsAg)] at 0, 1, 2, and 12 months in seronegative healthy adults.

RESULTS

At month 13, the anti-hepatitis B seroprotection rates (>10 mIU/mL) for the combined vaccine compared to the monovalent hepatitis B vaccine were 96.4% (95% CI: 92.7-98.5) and 93.4% (95% CI: 89.0-96.4), respectively. The anti-hepatitis A seroconversion rates were 100% in both groups (95% CI: 98.1-100). At day 37, the anti-hepatitis A seroconversion rates were similar in both groups (98.5% for combined vaccine, 98.6% for the monovalent vaccine group), but the combined vaccine resulted in a statistically significantly ( p < 0.001) better anti-hepatitis B seroprotection compared to monovalent hepatitis B vaccine, 63.2% versus 43.5%, respectively. The reactogenicity profile was similar in both study groups.

CONCLUSIONS

The combined hepatitis A and B vaccine administered on an accelerated schedule was at least as immunogenic and as well tolerated as the corresponding monovalent vaccines.

Risk of exposure to hepatitis B and other blood-borne viruses among Australians who travel abroad

BACKGROUND

European studies indicate that up to 67% of travelers traveling abroad participate in activities that put them at risk of exposure to hepatitis B. Australians are increasingly traveling to destinations where hepatitis B is highly endemic, such as Asia, and are likely to have similar levels of involvement in activities with an associated risk of hepatitis B exposure.

METHOD

A series of annual telephone surveys of approximately 500 randomly selected Australian overseas travelers have been conducted under the auspice of the Travel Health Advisory Group over the years 2001 to 2003. The surveys examined the extent to which travelers seek pretravel health advice, what immunizations they receive and what risks they are exposed to during travel including the risk of hepatitis B and other blood-borne virus acquisition.

RESULTS

In the 2003 survey, 281 (56%) of the 503 people interviewed had visited at least one country with high or medium hepatitis B endemicity on their most recent overseas trip in the past two years. Approximately a third of travelers undertook one or more activities that were considered to be associated with increased risk of potential hepatitis B exposure. Less than half the travelers (46%) had been vaccinated against hepatitis B.

CONCLUSIONS

The results have implications for the individual traveler, as well as to the broader community. Infected travelers can be an important source of hepatitis B into their own home communities. Improved advice and clear recommendations for hepatitis B vaccination are needed to avoid infection.

Hepatitis B risks and immunization coverage among American travelers

BACKGROUND

Hepatitis B is endemic in much of Asia, Africa, and parts of South America, regions that are increasingly popular destinations for American travelers. The frequency of hepatitis B risks during travel has been examined for Europeans but not Americans. Further, limited data are available to describe the domestic hepatitis B risk factors of American travelers, the proportion vaccinated, and whether immunization activities target travelers at highest risk. We conducted a survey of international travelers to address these issues.

METHODS

A survey was mailed to 884 American international travelers, of whom 618 (70%) responded. The survey covered demographic and travel characteristics, sources of pre-travel health advice, immunization status, and items needed to assess hepatitis B vaccination candidacy. Travel-specific items concerned the most recent trip to a hepatitis B endemic region. Hepatitis B risk during the most recent trip was classified as high, potential, or none based on potential exposure to blood or bodily fluids.

RESULTS

Only 31% of respondents visited any health practitioner to obtain pre-travel health advice; 13% visited a travel medicine specialist. Totally 45% of respondents reported (3)1 domestic or travel-related hepatitis B risk, and 8% were at high risk during travel. Risk factors were more common among younger travelers and those with longer travel durations. Travel medicine specialists were more likely than nonspecialists to provide hepatitis B vaccine (40% vs 21%, p= 0.01). Travelers with risk factors were no more likely to be vaccinated in specialist or nonspecialist settings. Upon departure, only 19% of all travelers and 30% of travelers with risk factors had received three or more hepatitis B vaccine doses.

CONCLUSIONS

Most US travelers to hepatitis B endemic regions do not secure pre-travel health advice, and most have not received three doses of hepatitis B vaccine. A substantial share are candidates for hepatitis B vaccination based on their domestic activities, and/or face hepatitis B risks during travel.

Travel medicine interventions and neurological disease

As a consequence of increased mobility worldwide, persons with underlying medical conditions set out on a journey more often than in the past. Among pre-existing medical conditions, some neurological diseases, including multiple sclerosis and other demyelinating diseases, Guillain-Barré syndrome and myasthenia gravis often create management problems to travel medicine practitioners. There is some concern that these conditions could be worsened either by naturally acquired infections or by some travel medicine interventions. The aim of this review is to suggest a practical approach to each of these conditions and to examine the feasibility and the impact of travel medicine interventions on the underlying disease.

Should universal hepatitis B immunisation be introduced in the UK?

Yes. But how?

Hepatitis A and B Booster Recommendations: Implications for Travelers

Hepatitis A and B are serious vaccine-preventable diseases with a predominantly overlapping epidemiological distribution. Travelers, a term encompassing a range of individuals, are at risk of contracting these diseases if they are unvaccinated. Although the benefits of the primary vaccination course of hepatitis A and B vaccines are clear, the administration of hepatitis A and B boosters varies worldwide. Recommendations on the need for booster vaccinations have recently been published, and the implications of these recommendations for travelers are discussed in this review. Until a greater understanding is reached on the immunogenicity of hepatitis A and B vaccines in certain special groups (e.g., immunocompromised persons), there will be a need to monitor antibody levels to assess whether booster vaccinations are required. However, for the majority of immunocompetent travelers, the full primary vaccination course will provide protection from both hepatitis A and B infection in the long term, without the need for boosters.

Travel-related hepatitis B: risk factors and prevention using an accelerated vaccination schedule

Rates of global travel and tourism are increasing dramatically, especially to regions with medium or high endemicity for hepatitis A and B, such as Asia, Africa, Latin America, and the Middle East. International travelers to these areas should be protected against both hepatitis A and B, regardless of their anticipated length of stay. However, many travelers depart within weeks of planning their trip (too late to complete the accelerated 0-, 1-, 2-month regimen for hepatitis B), and a majority of those traveling depart without being vaccinated. Although extended-stay travelers are at high risk for hepatitis B, short-stay travelers also are at risk. The most commonly encountered risk factors for travel-related hepatitis B are casual sexual activity with a new partner, medical and dental care abroad, and in the expatriate community, adoption of children who are hepatitis B carriers. Although efficacy studies of accelerated schedules for hepatitis B immunization have not been conducted, the results of immunogenicity studies in healthy volunteers who received an accelerated, 3-dose regimen on a 0-,7-, and 21-day schedule suggest that excellent, rapid, and long-term protection will be conferred. More data are needed to assess the efficacy of accelerated schedules in persons aged >40 years and to determine whether a fourth dose of hepatitis B vaccine is needed in all age groups.

A review of the efficacy, immunogenicity and tolerability of a combined hepatitis A and B vaccine

Hepatitis A and B are two of the most common vaccine-preventable liver diseases and continue to be a significant cause of morbidity and mortality worldwide, with their severity related to the individual's age upon initial infection. Twinrix (GlaxoSmithKline), a combined vaccine providing protection against both hepatitis A and B, has been available in more than 72 countries worldwide since 1997. This paper provides a critical review of clinical data on the efficacy, immunogenicity and tolerability of the combined vaccine, with particular focus on the clinical benefits of dual vaccination.

Travelers' knowledge, attitudes and practices on the prevention of infectious diseases: results from a study at Johannesburg International Airport

BACKGROUND

Although Johannesburg International Airport (JIA) acts as a hub for travel into Africa, little was known of the knowledge, attitudes, and practices (KAP) with respect to infectious disease prevention of departing travelers.

METHODS

The study was conducted among departing passengers at JIA from August to October 2003. Travelers aged at least 18 years, resident in non-malarious developed countries and departing from JIA for risk destinations, were given either a malaria (Q-mal, n=219) or vaccine-preventable disease (Q-vac, n=200) questionnaire. European Travel Health Advisory Board traveler KAP questionnaires were used.

RESULTS

African destinations accounted for 99% of the total. Traveler mean age was 42 years, with 30% aged 50 years or above. Leisure (42%) and business (37%) were the commonest travel reasons; 8% of subjects were visiting friends or relatives. Forty-six per cent of travelers prepared for their trip at least 1 month in advance; 86% had sought pre-travel health advice, with travel clinics and the Internet being rated highest by travelers for quality of advice. World Health Organization immunization guidelines were followed poorly: only 37% and 27%, respectively, of travelers had demonstrable proof of protection against hepatitis A and B, with 40% of all Q-vac travelers unable to produce a vaccination certificate. Of travelers to yellow fever- endemic countries, 76% were able to produce a valid vaccination certificate; 22% of travelers to countries not endemic for yellow fever had nevertheless been specifically immunized against yellow fever for their journeys. Forty-nine per cent of Q-mal travelers carried either no or inappropriate antimalarials.

CONCLUSIONS

Considerable deficiencies in KAP were documented with regard to travel vaccinations and malaria protection in travelers departing JIA. Improved vaccine uptake and antimalarial prescribing are required for travelers to Africa.

Vaccination options for last-minute travellers in need of travel-related prophylaxis against hepatitis A and B and typhoid fever: a practical guide

Last-minute travellers represent a particular challenge to travel healthcare professionals, as standard vaccination schedules can take a few months to complete. This has led researchers to investigate the value of alternative accelerated schedules and existing schedules among this group, particularly with respect to time taken for an individual to seroconvert, duration of protection and multiple vaccination requirements. This paper reviews the available options for the three most common vaccine preventable diseases among travellers-hepatitis A, hepatitis B and typhoid fever. Studies suggest that even if the first dose of hepatitis A vaccine is given on the day of travel, this will provide adequate protection, and that immunity to typhoid fever can be provided in over 70% of travellers following vaccination 1 week prior to departure. For hepatitis B, an accelerated schedule of 0, 7 and 21-days has been shown to induce early protection, and is considered to be of benefit to the last-minute traveller. Practical guidelines on vaccination options from one week up to one month, as well as one month or more prior to travel are presented. This should provide guidance for travel healthcare professionals, and reassure last-minute travellers that they need not begin their journey unprotected against these three serious infectious diseases.

Travelers' knowledge, attitudes, and practices on prevention of infectious diseases: results from a pilot study

BACKGROUND

The European Travel Health Advisory Board conducted a cross-sectional pilot survey to evaluate current travel health knowledge, attitudes, and practice (KAP) and to determine where travelers going to developing countries obtain travel health information, what information they receive, and what preventive travel health measures they employ.

METHOD

Trained interviewers invited passengers at the departure gates of three international airports: London Heathrow, Paris Charles de Gaulle, and Munich to respond to a self-completion questionnaire. A total of 609 responses were collected.

RESULTS

The study showed that more than one-third of travelers questioned had not sought pretravel health advice and of those who did, over 20% sought advice 14 days or less prior to travel. One-third of the respondents were aged 50 or more, and 20% had planned their trip less than 2 weeks before leaving. Only a minority were able to demonstrate that they had been immunised as per the World Health Organization or national recommendations. Respondents often misperceived both the risk of malaria at the destination and recommended preventive measures.

CONCLUSIONS

The results of this pilot survey provided a valuable insight into the KAP of travelers and highlighted an important educational need among those traveling to risk destinations. Strategies are needed for raising awareness of preventable travel health issues and for raising compliance with existing recommendations.

Vaccination priorities

Selection of immunizations should be based on requirements and on risk of infection. According to the International Health Regulations, many countries require yellow fever vaccination and proof thereof as the International Certificate of vaccination. Additionally selected countries require proof of vaccination against cholera and meningococcal disease. A consultation for travel health advice is always an opportunity to ascertain that routine immunizations have been performed. Recommended immunizations often are more important for traveller's health than the required or routine ones. The most frequent vaccine preventable infection in non-immune travellers to developing countries is hepatitis A with an average incidence rate of 0.3% per month; in high risk backpackers or foreign-aid-volunteers this rate is 2.0%. Many immunizations are recommended for special risk groups only: there is a growing tendency in many countries to immunize all young travellers to developing countries against hepatitis B, as it is uncertain who will voluntarily or involuntarily get exposed. The attack rate of influenza in intercontinental travel is estimated to be 1%. Immunity against poliomyelitis remains essential for travel to Africa and parts of Asia. Many of the 0.2-0.4% who experience an animal bite are at risk of rabies. Typhoid fever is diagnosed with an incidence rate of 0.03% per month among travellers to the Indian subcontinent, North and West Africa (except Tunisia), and Peru, elsewhere this rate is 10-fold lower. Meningococcal disease, Japanese encephalitis, cholera and tuberculosis have been reported in travellers, but these infections are rare in this population. Although no travel health vaccine is cost beneficial, most professionals will offer protection against the frequent risks, while most would find it ridiculous to use all available vaccines in every traveller. It is essentially an arbitrary decision made on the risk level one wishes to recommend protection--but the priorities need to be set correctly.

Recent Advances and New Challenges in Travel Medicine

Recent advances in travel medicine include the use of computer resources to obtain information on outbreaks and recommendations to travelers, the introduction of atovaquone/proguanil as chemoprophylaxis and treatment for malaria, the use of azithromycin as an alternative in the self-treatment of traveler's diarrhea, and the combination of hepatitis A and hepatitis B vaccines. At the same time, new challenges continue to appear. Shifts in the distribution of infections, such as West Nile virus and dengue fever, underscore the need for up-to-date information. Well-known infectious diseases, such as polio, meningococcal meningitis, and influenza are appearing in unexpected ways and settings. It is increasingly clear that travelers, while at risk for infections, also play a role in the global dispersal of pathogens, such as certain serogroups of Neisseria meningitidis and influenza. Increasing drug resistance affects the choice of drugs for treatment and chemoprophylaxis, and decisions about use of vaccines. Newly identified adverse events associated with yellow fever vaccine have prompted enhanced surveillance after vaccination and careful scrutiny of appropriate indications for the vaccine.