Hepatitis A and B Vaccination in Elderly Travellers with risks increasing with advancing age.16 In adults, about half of new


These increased morbidity and mortality risks in older adults underscore the need for effective pre-exposure vaccination of those who are non-immune when travelling to areas of high HAV and/or HBV endemicity.19


HBV infections are symptomatic and fulminant hepatitis occurs in 1–2% of acutely infected individuals,17 subjects.18


with the highest risk in elderly


responses for HAV and HBV in elderly individuals is compromised by senescence of the immune system,20,21


vulnerability of the elderly to HAV and HBV infections.


Focusing on the older traveller, this article describes the following: risk factors for acquisition of HAV and HBV; implications of infection; immunogenicity and safety profile of available vaccines; vaccination recommendations; and awareness and attitude of travellers to preventive measures.


Hepatitis A Epidemiology


The mode of transmission of HAV is via the faecal-oral route, most commonly by person-to-person contact.22


HAV has a global


distribution (see Figure 1) and incidence is strongly correlated with socioeconomic indicators and with access to clean drinking water. Current estimates suggest that high-income regions have low HAV endemicity, low-income regions have high endemicity and middle-income regions have a mix of intermediate and low endemicity.23


potentially increasing the


Figure 1: Prevalence of Antibody to Hepatitis A Virus, 2006 (Centers for Disease Control and Prevention)


However, the development of vaccine


Prevalence of antibody to hepatitis Avirus High


Intermediate Adapted from Travelers’ Health – Yellow Book, 2010.127


susceptible populations also means a greater likelihood of outbreaks in intermediate endemicity countries transitioning to a lower HAV endemicity, as recently observed in Belarus,33,34 Kazakhstan,36,37 Ukraine.34,44


Latvia,38 Russia,34,39,40 Serbia,41 Slovakia,42


the Czech Republic,35 Spain43


and


HAV infection usually produces an asymptomatic infection in children younger than six years of age, who then experience lifelong immunity. However, infection in older children and adults usually leads to clinical disease, consisting of gastrointestinal and influenza-like symptoms, often followed by several weeks of jaundice, with a greater severity of disease in older adults.16


Fatalities


due to hepatitis A are more common with advancing age and in patients with chronic hepatitis B or C.24–26


of acute hepatitis A in the US in 2007 were 0% in infants and children <15 years of age, 0.3% between the ages of 15 and 39, 0.8% between the ages 40 and 59, and 2.6% in those aged 60 or over.27


In countries of high endemicity, nearly all individuals are infected with HAV at an early age. In industrialised (low endemicity) countries, rates of HAV infection have declined as socioeconomic conditions and standards of hygiene have improved. Estimates of anti-HAV seroprevalence in Western Europe in 2005 were 63% in the 35–44 years of age group, 73% in the 45–54 years of age group, 83% in the 55–64 and 92% in 65–74 years of age group, respectively.23


Due to the


The burden of disease in these countries occurs mainly in adolescents and adults in high-risk populations such as travellers to high endemicity countries, men who have sex with men and injection drug users (IDUs).5,31


Shifts in Hepatitis A Virus Endemicity and Risk of Infection


Changes in epidemiological patterns of HAV associated with improved sanitation and living standards mean that more countries are now shifting from high to intermediate endemicity, resulting in an increasing proportion of adults that have no immunity to HAV and who are susceptible to symptomatic infection.23,32


An increase in the size of EUROPEAN GASTROENTEROLOGY & HEPATOLOGY REVIEW


changing HAV epidemiology, an increasing proportion of adults have therefore never encountered the virus in childhood and are susceptible to infection (and increased risk of symptomatic disease).28–30


Reported case fatality rates


In 2008, morbidity from HAV infection was greatly increased throughout the Czech Republic, more than was predicted, based on observations from previous years.2


Hepatitis A in International Travellers


Determinants of contracting HAV infection in non-immune international travellers include country of origin, travel destination, duration of stay and personal habits during travel.45


The destinations


HAV incidence per month among non-immune Swiss travellers to high-risk destinations was 6.0–28.0 cases per 100,000 travellers, with the highest rates for travel to sub-Saharan Africa and south-central Asia.11


were reported during the period 1997 to 2005.46


In Sweden, 636 cases of travel-related hepatitis A The highest incidence


rate was following travel to East Africa (14.1 cases per 100,000 travel months), followed by Middle East (5.8 per 100,000 travel months), and India and neighbouring countries (5.6 per 100,000 travel months). In an Italian survey, during the period 1996–2000, 28% of HAV infections were travel-related.47


While Asia, Africa and Latin America posed the highest risk (odds ratio [OR] = 9.30), there was also an increased risk for travel to Southern Italy (OR = 3.03) and to the Mediterranean area and Eastern Europe (OR = 3.15). The actual incidence of travel-related HAV may be generally higher than noted due to under-reporting of the diagnosis of acute hepatitis A when abroad.6


The risk of HAV infection is increased for travellers exposed to poor hygienic conditions (such as backpackers).48


Older travellers have a


greater tendency to stay in better standards of accommodation, but this does not eliminate the risk of infection. In August 2004, an outbreak of hepatitis A occurred in European tourists who had stayed in a luxury hotel in Egypt; fruit juice was implicated as the source of HAV.49


Outbreaks have also occurred from the consumption of certain shellfish (bivalve molluscs such as mussels, oysters and clams that feed by filtering large volumes of sewage-polluted waters)50,51 salad vegetables.52–54


and 85


that pose the highest risk of HAV infection for international travellers are Africa, Latin America, the Indian subcontinent, the Middle East and Eastern Europe.45


Low


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84