Waner S, Schoub BD, Baxter AM, French D
Travel Clinic, South African Institute for Medical Research, University of the Witwatersrand.
J Travel Med. 1997 Dec 1;4(4):192-194. doi: 10.1111/j.1708-8305.1997.tb00820.x.
Hepatitis A is an important cause of acute hepatitis in travelers to developing countries. In 1991, 33 million persons living in industrialized countries traveled to developing countries where hepatitis A is highly endemic (World Tourism Organization, unpublished data, 1993). Reports indicate that 40-50% of cases of hepatitis A infection in the United Kingdom,1 Switzerland2 and Sweden3 are associated with recent international travel. The disease is usually benign, but the severity increases with age.4 Because the disease is enterically transmitted, occurrence is related to water quality and level of sanitation. In developing countries, with poor water quality and sanitation, especially in the tropics where hepatitis A is endemic, exposure is virtually universal before the age of 10 years.4 In developed countries with good food and water hygiene, the rate of exposure to hepatitis A in children is low. The rate of seropositivity increases slowly during early adulthood and reaches moderate levels during late adulthood.5 Studies have demonstrated the higher prevalence among people who live in poor, overcrowded conditions.6 Travelers going from low incidence countries to endemic areas are particularly at risk for acquiring hepatitis A, especially if they stay for extended periods.7 The risk that Danish travelers to North Africa would acquire hepatitis A was estimated to be 3.5 per 10,000, and this population accounted for at least 20% of all cases of hepatitis in Denmark. Similarly, Germans traveling or living in tropical countries have a 40 times higher risk of acquiring hepatitis than do groups living at home.8 The pattern in South Africans ranges from minimal exposure to hepatitis A in childhood in populations with good water quality and sanitation (mainly white), to high exposure in those exposed to poor water quality and sanitation in childhood (mainly black). Hepatitis A vaccine has been found to be effective in reducing the incidence of infection in travelers. After the introduction of hepatitis A vaccine into Switzerland in 1992, there has been a reduction by 15% in the cases of imported hepatitis A.9 Hepatitis A vaccine should be offered to South African travelers to high risk areas.10,11 However for the vaccine to be the most cost-effective, it would be important to identify groups of travelers who would benefit from empiric vaccination as opposed to other groups who should undergo screening prior to vaccination. This study was undertaken to establish the seroprevalence of hepatitis A in the South African traveler and to identify groups of travelers that should be vaccinated.
甲型肝炎是前往发展中国家的旅行者急性肝炎的重要病因。1991年，生活在工业化国家的3300万人前往甲型肝炎高度流行的发展中国家（世界旅游组织，未公布数据，1993年）。报告显示，英国1、瑞士2和瑞典3中40%-50%的甲型肝炎感染病例与近期国际旅行有关。该疾病通常为良性，但严重程度随年龄增长而增加。4由于该疾病通过肠道传播，其发生与水质和卫生水平有关。在水质和卫生条件差的发展中国家，尤其是在甲型肝炎流行的热带地区，10岁前几乎普遍接触过该病毒。4在食品和水卫生良好的发达国家，儿童接触甲型肝炎的几率较低。血清阳性率在成年早期缓慢上升，在成年后期达到中等水平。5研究表明，生活在贫困、拥挤环境中的人群患病率较高。6从低发病率国家前往流行地区的旅行者感染甲型肝炎的风险尤其高，特别是如果他们停留较长时间。7据估计，前往北非的丹麦旅行者感染甲型肝炎的风险为每10000人中有3.5人，该人群占丹麦所有肝炎病例的至少20%。同样，前往热带国家旅行或生活的德国人感染甲型肝炎的风险比国内人群高40倍。8南非的情况各不相同，水质和卫生条件良好的人群（主要是白人）儿童时期接触甲型肝炎的几率极低，而儿童时期接触水质和卫生条件差的人群（主要是黑人）接触几率很高。已发现甲型肝炎疫苗可有效降低旅行者的感染率。1992年瑞士引入甲型肝炎疫苗后，输入性甲型肝炎病例减少了15%。9应向前往高风险地区的南非旅行者提供甲型肝炎疫苗。10,11然而，为了使疫苗具有最高的成本效益，确定哪些旅行者群体将从经验性接种中受益，而不是哪些群体在接种前应进行筛查，这一点很重要。本研究旨在确定南非旅行者中甲型肝炎的血清流行率，并确定应接种疫苗的旅行者群体。
