Hepatitis B immunisation in travellers: poor risk perception and inadequate protection.

OBJECTIVES: A survey of European travellers was conducted during 2006 to determine travellers' immunisation status and risk for exposure to hepatitis B while travelling. DESIGN: A first telephone (Omnibus) survey established the prevalence of travel in the previous five years as well as demographic profile of travellers amongst the general population. A second online survey targeted travellers to moderate or high hepatitis B endemicity countries, using data from the first survey to ensure a final sample representative of the travelling population in each country. Self-reported vaccination status and participation in activities/situations at high risk of exposure to hepatitis B were recorded. PARTICIPANTS: A total of 5948 interviewees participated in the first (Omnibus) survey and 4151 travellers completed the online survey. SETTING: Belgium, Italy, Finland, Germany, Netherlands, Spain, Sweden and UK. RESULTS: Only 15% of 4151 travellers to endemic countries recalled specifically receiving hepatitis B vaccination. Fifty-one percent of travellers to endemic countries visited a health care professional (HCP) before travelling. Of these, 54% did not receive any hepatitis B vaccination. Fifty percent of all respondents had never discussed risk factors for hepatitis B infection with a health care professional. Altogether, 1 in 4 travellers were at increased risk for exposure to hepatitis B due to hospitalisation, sexual activity or body piercing/tattooing amongst others. Three percent of travellers to high risk destinations were health tourists of which 65% did not recall being vaccinated against hepatitis B. CONCLUSION: Compared to a previous survey, this follow on survey 7 years later indicates the risk of exposure to hepatitis B has increased, but not hand-in-hand with the protection of travellers against hepatitis B through vaccination: travellers to at risk destinations continue to be unvaccinated against hepatitis B, including those who visit health care practitioners prior to travelling. Advice regarding hepatitis B immunisation for travel is received infrequently and travellers remain unaware of the risks of hepatitis B associated with travel. Many high risk situations are not predictable prior to travel, supporting an all-inclusive approach to hepatitis B vaccination in travellers.

The true burden and risk of cholera: implications for prevention and control.

Cholera is a substantial health burden on the developing world and is endemic in Africa, Asia, South America, and Central America. The exact scale of the problem is uncertain because of limitations in existing surveillance systems, differences in reporting procedures, and failure to report cholera to WHO; official figures are likely to greatly underestimate the true prevalence of the disease. We have identified, through extensive literature searches, additional outbreaks of cholera to those reported to WHO, many of which originated from the Indian subcontinent and southeast Asia. Such underestimation of cholera can have important implications for decisions on provision of health interventions for indigenous populations, and on risk assessments for travellers. Furthermore, until recently, it has not been possible to implement public-health interventions in low-income countries to eliminate disease, and the prevention of cholera in travellers has been limited to restrictive guidelines. However, a vaccine against cholera is now available that has proven efficacy and tolerability in mass vaccination campaigns in low-income countries, and among travellers.

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.

Review of current typhoid fever vaccines, cross-protection against paratyphoid fever, and the European guidelines.

INTRODUCTION: Typhoid and paratyphoid fever remain a global health problem, which - in non-endemic countries - are mainly seen in travelers, particularly in VFRs (visiting friends and relatives), with occasional local outbreaks occurring. A rise in anti-microbial resistance emphasizes the role of preventive measures, especially vaccinations against typhoid and paratyphoid fever for travelers visiting endemic countries. Areas covered: This state-of-the-art review recapitulates the epidemiology and mechanisms of disease of typhoid and paratyphoid fever, depicts the perspective of non-endemic countries and travelers (VFRs), and collectively presents current European recommendations for typhoid fever vaccination. We provide a brief overview of available (and developmental) vaccines in Europe, present current data on cross-protection to S. Paratyphi, and aim to provide a background for typhoid vaccine decision-making in travelers. Expert commentary: European recommendations are not harmonized. Experts must assess vaccination of travelers based on current country-specific recommendations. Travel health practitioners should be aware of the issues surrounding vaccination of travelers and be motivated to increase awareness of typhoid and paratyphoid fever risks.

HIV and travel.

There is a high demand for travel among HIV-positive individual. This demand arises partly from those who have benefited from advances in antiretroviral therapy as well as those with disease progression. The key to a successful and uneventful holiday lies in careful pre-trip planning, yet many patients fail to obtain advice before travelling. Travel advice for HIV patients is becoming increasingly specialized. In addition to advice on common travel-related infectious diseases, HIV-positive travellers are strongly advised to carry information with them and they need specific advice regarding country entry restrictions, HIV inclusive travel insurance, safety of travel vaccinations and highly active antiretroviral therapy-related issues. A wide range of relevant issues for the HIV-positive traveller are discussed in this review and useful websites can be found at the end.

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.

The place of accelerated schedules for hepatitis A and B vaccinations.

The availability of accelerated schedules of vaccination, as well as the development of combination vaccines, has enhanced the methods of protection against infectious disease, in particular that of hepatitis A and B viruses. The benefits of using accelerated schedules include: (i) enhanced adherence to and subsequent completion of vaccine courses; (ii) convenience for the recipient of the vaccine; (iii) reduced administration costs of providing the vaccine; and, most importantly, (iv) the ability to provide protection against these serious infections to those who will be imminently exposed to the risk and so require protection as quickly as possible. Active immunisation against both hepatitis A and B viruses has only been recognised within the last 20 years. During this time clinical studies have demonstrated the safety and efficacy of administering the monovalent hepatitis B vaccine by way of accelerated schedules. There are now several accelerated schedules of administration of hepatitis B vaccine which can be tailored to the needs of the individual at risk of exposure to infection. One such schedule allows the primary course to be administered within a period of 1 month. This schedule of day 0, 7 and 21, with a booster at 12 months, is licensed for use with the recombinant hepatitis B vaccine Engerix B and results in a seroprotection rate of 65% at day 28 which increases to 99% at month 13. In more recent years, the development of a multivalent or combination vaccine against hepatitis A and B (Twinrix) has been a welcome advance in the protection against viral hepatitis, and has been of particular benefit to those who are at risk of infection with both viruses. The advantages of accelerated schedules have also been recognised with this combination vaccine. The primary course may be administered within a period of 1 month so providing protection for those at risk and, in particular, the last minute traveller.

Mutations of the surface protein of hepatitis B virus.

Neutralizing antibodies induced by immunization against hepatitis B infection are targeted to the conformational epitopes of the common a determinant of the surface antigen. However, amino acid substitutions within this region of the surface protein of the virus, particularly in the region of amino acid 137-147 allow replication of hepatitis B virus in vaccinated subjects, since antibodies induced by current vaccines do not recognize crucial changes in the surface antigen domain. The G145R mutant is replication competent and is stable, and it appears to be the most common variant. There is evidence that these mutants may not be detected by current screening tests and diagnostic reagents. Epidemiological monitoring of hepatitis B virus surface mutants is essential.

Recombinant hepatitis B triple antigen vaccine: Hepacare.

Infection with hepatitis B virus is a public health problem throughout the world. Hepatitis B vaccines are now included in national immunization programmes of infants and/or adolescents in 129 countries. Current single antigen vaccines, that are plasma-derived or produced by recombinant DNA technology are highly effective, but between 5-10% or more of healthy immunocompetent subjects do not mount an antihepatitis B surface antibody protective response and others respond poorly (hyporesponders). The inclusion of pre-S1 and -S2 components of hepatitis B surface antigen in addition to the single antigen (triple antigen) in a novel vaccine, Hepacare, Medeva Pharma Plc, Speke, UK, overcomes nonresponsiveness and hyporesponsiveness in a significant number of individuals. The triple antigen is indicated for vaccination of nonresponders (and hyporesponders) to the current single antigen vaccines and for persons who require rapid protection against hepatitis B infection.

Impact of the insect biting nuisance on a British youth expedition to Alaska.

BACKGROUND: The morbidity and nuisance factor associated with bites from mosquitoes and other insects are one of the many hazards faced by travelers, including those to the Arctic. A predeparture literature review suggested that insect bites were such a large problem in the area to be visited that they would probably have a significant impact on expedition activities. Therefore, we set out to assess the extent of the insect biting nuisance, focussing particularly on interference with expedition activities, in order to make recommendations for future expeditions to this area. The number of bites and their effects was examined on a 6-week British youth expedition to Alaska in July/August 1999. METHODS: A weekly "Insect Biting Nuisance Questionnaire" was distributed to each expedition member (total 72) to record the number of bites received over the previous week, a subjective grading of severity and itchiness, the extent of interference with expedition activities, any complications from the bites, and details about prevention and treatment. RESULTS: The questionnaire response rate was 64%, which was a representative sample. The median number of bites per person over the entire 6-week period was 33, with females and younger expeditioners tending to receive more bites. Multivariate analysis suggested that younger age was associated with more severe and itchier bites. Sleep was disturbed by itching on only 4% (68/1918) of nights. Generally, the bites were thought not to interfere with expedition activities (median score for interference 0; range 0-10). CONCLUSION: The number of bites and their impact on expedition activities were both lower than expected. Thus, it is recommended that expeditions and independent travelers to this area do not need to increase time spent in the field to compensate for expedition man days lost due to problems associated with the insect biting nuisance.

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.

Knowledge, attitudes and practices in travel-related infectious diseases: the European airport survey.

BACKGROUND: The European Travel Health Advisory Board conducted a cross-sectional pilot survey to evaluate current travel health knowledge, attitudes and practices (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. Subsequently, the questionnaire used was improved and a cross-sectional, multicenter study was undertaken in airports in Europe, Asia, South Africa and the United States. This paper describes the methods used everywhere, and results from the European airports. METHOD: Between September 2002 and September 2003, 5,465 passengers residing in Europe and boarding an intercontinental flight to a developing country were surveyed at the departure gates of nine major airports in Europe. Questionnaires were self-administered, and checked for completeness and validated by trained interviewers. RESULTS: Although the majority of travelers (73.3%) had sought general information about their destination prior to departure, only just over half of the responders (52.1%) had sought travel health advice. Tourists and people traveling for religious reasons had sought travel health advice more often, whereas travelers visiting friends and relatives were less likely to do so. Hepatitis A was perceived as the most probable among the infectious diseases investigated, followed by HIV and hepatitis B. In spite of a generally positive attitude towards vaccines, 58.4% and 68.7% of travelers could not report any protection against hepatitis A or hepatitis B, respectively. Only one in three travelers to a destination country with at least some malaria endemicity were carrying antimalarial drugs. Almost one in four travelers visiting a high-risk area had an inaccurate risk perception and even one in two going to a no-risk destination were unnecessarily concerned about malaria. CONCLUSIONS: The large variation in destinations, age of the travelers and reasons for traveling illustrates that traveling to a developing country has become common practice. The results of this large-scale airport survey clearly demonstrate an important educational need among those traveling to risk destinations. Initiatives to improve such education should target all groups of travelers, including business travelers, those visiting friends and relatives, and the elderly. Additionally, travel health advice providers should continue their efforts to make travelers comply with the recommended travel health advice. Our common objective is to help travelers stay healthy while abroad, and consequently to also reduce the potential importation of infectious diseases and the consequent public health and other implications.

Hepatitis E and the traveller.

The risk of infection with hepatitis E virus to international travellers to endemic regions such as the subcontinent of India, Nepal, South-East Asia, China, parts of the Middle East, Africa, Mexico and some countries of South America is underestimated. Hepatitis E virus is transmitted enterically usually by drinking water contaminated by sewage and also by raw or uncooked shellfish. Outbreaks occur in number of hot climate countries where the infection is endemic, and a zoonotic element may be significant both in endemic areas and in developed countries where sporadic cases also occur. The clinical course of the infection can be severe with high mortality of up to 20% during the third trimester of pregnancy. Advice to travellers must include strict precautions with regard to drinking water and the consumption of raw food. Specific prophylaxis and treatment against hepatitis E infection are not available at present. Specific immunoglobulin and several recombinant and subunit vaccines are under development. One baculovirus, expressed viral protein vaccine is under phase II/III trial in Nepal.

The traveller and West Nile virus.

Infection with West Nile virus is a zoonosis which has emerged recently as a threat to public health and animal health in temperate regions in parts of Europe and more extensively in North America. Most infections are asymptomatic, 20% lead to a mild febrile illness and about 1% result in severe neurological disease, particularly in those over the age of 50 years. West Nile virus is transmitted by mosquitoes and the principal hosts are numerous species of wild birds. There is no specific treatment and a vaccine is not available. Prevention in areas where the virus is circulating is based on protection from mosquito bites and reduction and control of the number of mosquitoes in the environment. The risk to travellers is not known at present, but appears to be low in terms of symptomatic illness.

Poliovirus immunisation for travellers.

Mass immunisation against poliomyelitis using principally oral live attenuated trivalent vaccine (OPV) has eradicated wild-type poliovirus transmission in the industrialised countries of the Western hemisphere and most other countries, and the global eradication of poliomyelitis is within reach. The risk of oral polio vaccine-associated poliomyelitis has been estimated by WHO at 0.5-3.4 cases per million of susceptible children, and by the Centers for Disease Control and Prevention (USA) at 1 case per 2.4 million doses of OPV. This has led to the reintroduction and use of inactivated vaccine in the USA and a number of other countries. The current risk of poliomyelitis for travellers is reviewed together with the application of strategies for immunisation against these infections.

Cholera: assessing the risk to travellers and identifying methods of protection.

This review is based on the findings of a consultation meeting involving consultants in travel medicine and focusing on the risks of cholera to the traveller. Cholera is a severe diarrhoeal disease transmitted via the faeco-oral route and commonly associated with poor sanitation. Between the years of 1995 and 2001, the WHO reported 1829 cases of cholera in developed countries, the majority of which were imported. However, it is believed that this figure reflects less than 10% of the true incidence of cholera due to milder cases being unrecognised, as well as significant underreporting. Travellers to epidemic countries may be at increased risk of contracting cholera if they ingest contaminated food or water. It has been estimated that there are 0.2 cases of cholera per 100,000 European and North American travellers, though there is some evidence that this rate is higher. Oral vaccines are a necessary and welcome advance as, in addition to preventing illness, they can minimise the possibility of transmission of cholera to disease-free regions. The morbidity from cholera can range from asymptomatic or oligosymptomatic infection to disruption of holiday and business plans, or even severe toxicity and dehydration. If untreated, severe illnesses can be fatal, although fatalities have not been reported among travellers for many years.

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.

The role of standby emergency medication for falciparum malaria: current opinion.

Travellers to malaria-endemic destinations are at risk of significant disease and, sometimes, death. Current malaria protection strategies, including chemoprophylaxis, can never be completely effective. In some cases, protective measures are discontinued or misapplied while the risk of infection still exists. In others, suboptimal measures are used, or even no measures at all, because of poor information or inappropriate risk-benefit assessment. In very rare cases, inexplicable failure of prophylaxis occurs. If malaria is contracted whilst abroad the danger to the individual is often further compounded by a lack of high-quality medical facilities and an uncertain supply of effective drugs for treatment. The advent of newer, well tolerated, drugs for treating malaria provides an opportunity to review the role of standby emergency self-medication in travellers visiting or staying (for work or other reasons) in areas where there is a risk of contracting malaria. This article was prepared following a meeting convened in London on Africa Malaria Day in 2002, in which the current opinions of experts in travel medicine and specifically malaria were discussed. It reviews opinion on the current effectiveness and acceptance of prevention strategies, as well as the role of standby emergency medication for falciparum malaria.

Meningococcal W135 carriage; enhanced surveillance amongst east London Muslim pilgrims and their household contacts before and after attending the 2002 Hajj.

BACKGROUND: For two successive years, 2000 and 2001, there was a world-wide outbreak of W135 meningococcal disease amongst pilgrims who attended the Hajj and in their contacts after returning home. METHODS: Beginning January 2002, we offered meningococcal quadrivalent polysaccharide vaccine (against serogroups A, C, Y and W135) to pilgrims and collected a throat swab for meningococcal W135 carriage before and after their pilgrimage. RESULTS: The overall Neisseria meningitidis carriage pre-Hajj was 8.3% and 6.3% post-Hajj. We found W135 carriage rates of 0.8% before and 0.6% after Hajj, respectively. 21% (36/174) of the pilgrims were treated with antibiotics for respiratory illness. CONCLUSION: The carriage of meningococcus W135 among UK pilgrims who visited the Hajj in 2002 was low. This contrasts with another study suggesting pilgrims frequently acquired N. meningitidis W135 carriage during 2001 Hajj. The use of the quadrivalent vaccine may account for this difference.