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.

Awareness of meningococcal disease among travelers from the United Kingdom to the meningitis belt in Africa.

Meningococcal disease causes considerable morbidity and has a high case-fatality rate. In the United Kingdom, the meningococcal quadrivalent vaccine is recommended for travelers visiting the meningitis belt of Africa. We analyzed 302 responses to a cross-sectional study conducted in 2010 of travelers who had visited the meningitis belt recently or were shortly due to travel there. Using the results of an online questionnaire, we assessed knowledge and understanding of meningococcal disease and likelihood of uptake of meningococcal immunization before travel. Meningococcal vaccine uptake was 30.1%. Although global scores in the questionnaire did not correlate with vaccine uptake, knowledge of the meningitis belt and knowledge of certain key symptoms or signs were statistically associated with high vaccine uptake. We conclude that improved education of travelers may improve vaccine uptake before travel to the meningitis belt in Africa.

Fever in the returning child traveller: approach to diagnosis and management.

During the last half century there has been an exponential increase in international travel including to more exotic and long-haul destinations. The assessment of febrile returning child travellers presents diagnostic challenges and is often performed poorly. A detailed travel and medical history, clinical examination and appropriate first-line investigations are essential. While the majority of children will have a common self-limiting or easily treatable infection, it is important to consider other causes, including imported infections, which may be life-threatening or highly contagious. In this article, we provide guidance on the initial assessment and management of such children with a focus on some of the more important imported infections, including malaria, dengue, typhoid fever, travellers' diarrhoea, respiratory infections, tuberculosis, schistosomiasis and rickettsial diseases.

Prevention of influenza among travellers attending at a UK travel clinic: beliefs and perceptions. A cross-sectional study.

BACKGROUND: Travellers' compliance with measures to prevent influenza through the use of antivirals and influenza vaccine remains very poor despite influenza being one of the commonest travel and vaccine-preventable diseases. A study was undertaken to assess travellers' beliefs, perceptions and intentions to take antivirals for the treatment and prevention of influenza during the H1N1 pandemic. METHODS: A cross-sectional survey (n = 96) of travellers who attended the Royal Free Travel Health Centre, London, UK was undertaken in September 2009. A self-administered questionnaire was completed by a traveller in advance of their pre-travel health consultation. Logistic regression identified variables independently associated with compliance. RESULTS: Influenza vaccination uptake for the 5 years preceding the study was found to be 20·8%. This was statistically significantly higher for older travellers and those with underlying health conditions (P < 0·005). Mean intention to comply with antiviral drugs on a preventive and therapeutic basis was 58% and 72%, respectively, and this varied markedly with age and with dispensed antimalarial chemoprophylaxis. CONCLUSION: This study identifies some beliefs and perceptions travellers consider with regard to the therapeutic and preventive influenza use of antivirals during the H1N1 pandemic; it underscores the importance of travellers receiving hemisphere appropriate influenza vaccination. The external validity of these study findings requires further corroboration involving other travel clinics and different cohorts of travellers during seasonal activity or outbreaks of influenza. These findings could guide the development of future strategies for the prevention of influenza in travellers.

Review of oral cholera vaccines: efficacy in young children.

BACKGROUND: Young children are one of the most vulnerable groups who may be infected with cholera. The following literature review of the efficacy of the currently available cholera vaccines provides a clear evidence base for the clinical administration of cholera vaccine, particularly in an epidemic situation. AIM: To assess the efficacy of oral cholera vaccines in preventing cases of cholera in young children. METHODS: A systematic literature review was undertaken for the period 1983 to 2011 using PubMed and the search terms "oral cholera vaccines," "children," and "efficacy," limited to "clinical trials" and "human studies". RESULTS: Oral cholera vaccine provides an acceptable level of protection in young children, with the level of protection being greater at 12 or 24 months following immunization. CONCLUSIONS: Children exposed to a potential risk of cholera are recommended to be vaccinated with an oral cholera vaccine, irrespective of whether its constituents include the B subunit.

2010 FIFA world cup South Africa: travel health issues and new options for protection against meningococcal disease.

The public health implications of large crowds gathering at a range of key global events should never be underestimated. This is especially the case with the upcoming 2010 FIFA World Cup South Africa programme where thousands of local and travelling spectators, players and officials from all over the world will be present. Although meningococcal disease contracted whilst actually travelling is relatively rare, any travel health risk assessment should involve consideration of potential exposure to and transmission of this disease where crowding occurs. In South Africa, for reasons not completely understood, the incidence of meningococcal disease is higher than in most European countries. Whilst the currently available polysaccharide vaccines can help protect travellers against meningococcal disease there are some well recognised limitations of such vaccines. These can, however, be overcome with the use of newly developed conjugated quadrivalent meningococcal vaccines. A quadrivalent conjugate vaccine should be the first choice for travellers to areas in which the risk of exposure to meningococcal disease is significant. The conjugated quadrivalent meningococcal vaccine should be recommended for all those attending or playing in the 2010 FIFA World Cup South Africa as well as similar global and regional events.

Effectiveness of malaria chemoprophylaxis against Plasmodium falciparum infection in UK travellers: retrospective observational data.

What is already known on this topic. Malaria is a potentially life-threatening disease, and cases of imported Plasmodium falciparum malaria have increased among UK travellers over the past 20 years, although declining steadily in recent years. The HPA Advisory Committee on Malaria Prevention (ACMP) UK Traveller guidelines recommend doxycycline, mefloquine, or combination atovaquone plus proguanil for prophylaxis in travellers to P. falciparum endemic regions, and with the exception of Lambeth Primary Care Trust, malaria chemoprophylaxis is not reimbursed by the NHS. There are limited data on the comparative effectiveness of the recommended malaria chemoprophylaxis drugs for P. falciparum. What this study adds. The effectiveness of combination atovaquone plus proguanil may provide greater protection against imported P. falciparum malaria in UK travellers as compared with doxycycline and mefloquine. More research is needed on the effectiveness of different chemoprophylactic regimens. Further work is required to ascertain whether ease of use and compliance may be important factors in the outcomes associated with malaria chemoprophylaxis.

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.

Immunogenicity and safety of an experimental adjuvanted hepatitis B candidate vaccine in liver transplant patients.

Patients with chronic liver disease are at higher risk of hepatitis B (HB) virus infection before and after liver transplantation, and they commonly have a suboptimal immune response to HB vaccines. In this randomized trial, we compared the immunogenicity of primary vaccination with 2 doses of an experimental adjuvanted HB vaccine (adjuvant system 04 containing aluminium and monophosphoryl lipid A [HB-AS04]) to that of 3 double doses of a licensed HB vaccine in 93 liver transplant candidates. Depending on the waiting list for liver transplantation, a booster dose of HB-AS04 or double booster dose of the licensed HB vaccine was given before or after surgery, at 6 to 12 months after initiation of the vaccination course. The percentage of subjects with seroprotective anti-HB surface antibody concentrations 1 month after booster was twice as high in the HB-AS04 group (60.0%), vs. patients in the comparator group (32.0%) (P = 0.035). In subjects who did not undergo liver transplantation before administration of the booster, better immunogenicity results were obtained: 80% of subjects were seroprotected after HB-AS04 vaccination vs. 60% with the comparator (P = 0.2302). Despite a slightly higher reactogenicity, the safety profile of the HB-AS04 vaccine was clinically acceptable. In conclusion, an improved antibody response was observed in liver transplant candidates with 3 doses of HB-AS04, as compared to 4 double doses of a comparator. Liver transplant candidates could benefit from the use of this experimental adjuvanted HB vaccine to further increase their protection against HB infection.

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.