Pediatrics. 2007 Jul;120(1):189-99. doi: 10.1542/peds.2007-1088.
Since licensure in 1995 of a hepatitis A vaccine, the Centers for Disease Control and Prevention and the American Academy of Pediatrics have been implementing an incremental hepatitis A immunization strategy for children. In 1996, children living in populations with the highest rates of disease were targeted for immunization, and in 1999 the program was expanded to immunization of children 2 years and older living in states and counties with rates of hepatitis A that historically have been higher than the national average. The 1999 program has been successful; the current rate of hepatitis A is the lowest ever reported in the United States. Regional, ethnic, and racial differences in the incidence of hepatitis A have been eliminated. The incidence of hepatitis A in adults in immunizing states has decreased significantly, suggesting a strong herd-immunity effect associated with immunization. In 2005, the US Food and Drug Administration changed the youngest approved age of administration of hepatitis A vaccine from 24 to 12 months of age, which facilitated incorporation of the vaccine into the recommended childhood immunization schedule. As the next step in the implementation of the incremental vaccine immunization strategy, the American Academy of Pediatrics now recommends routine administration of a Food and Drug Administration-licensed hepatitis A vaccine to all children 12 to 23 months of age in all states according to a Centers for Disease Control and Prevention-approved immunization schedule. Available data suggest that hepatitis A vaccine can be coadministered with other childhood vaccines without decreasing immunogenicity. Hepatitis A vaccines have proven to be extremely safe. In prelicensure clinical trials of both Havrix (GlaxoSmithKline, Rixensart, Belgium) and Vaqta (Merck & Co Inc, Whitehouse Station, NJ), adverse events were uncommon and mild when they occurred, with resolution typically in less than 1 day. Hepatitis A vaccine is contraindicated in people with a history of severe allergic reaction to a previous dose of hepatitis A vaccine or to a vaccine component. Because the hepatitis A vaccine is an inactivated product, no special precautions are needed for administration to people who are immunocompromised. No data exist about administration of the hepatitis A vaccine to pregnant women, but because it is not a live vaccine, the risk to mother and fetus should be extremely low to nonexistent.
自1995年甲型肝炎疫苗获得许可以来，疾病控制与预防中心及美国儿科学会一直在为儿童实施逐步推进的甲型肝炎免疫策略。1996年，将疾病发病率最高人群中的儿童作为免疫接种目标，1999年该计划扩大到对居住在甲型肝炎发病率历来高于全国平均水平的州及县的2岁及以上儿童进行免疫接种。1999年的计划取得了成功；目前美国甲型肝炎发病率为有记录以来的最低水平。甲型肝炎发病率的地区、种族和民族差异已消除。在实施免疫接种的州，成人甲型肝炎发病率显著下降，表明免疫接种具有强大的群体免疫效应。2005年，美国食品药品监督管理局将批准使用甲型肝炎疫苗的最小年龄从24个月改为12个月，这便于将该疫苗纳入推荐的儿童免疫接种计划。作为逐步推进的疫苗免疫策略实施的下一步，美国儿科学会现建议，根据疾病控制与预防中心批准的免疫接种计划，对所有州12至23个月大的儿童常规接种经美国食品药品监督管理局许可的甲型肝炎疫苗。现有数据表明，甲型肝炎疫苗可与其他儿童疫苗同时接种，而不会降低免疫原性。甲型肝炎疫苗已被证明极其安全。在Havrix（葛兰素史克公司，比利时里克森萨特）和Vaqta（默克公司，新泽西州怀特豪斯站）的上市前临床试验中，不良事件罕见，一旦发生也很轻微，通常不到1天即可缓解。对先前剂量的甲型肝炎疫苗或疫苗成分有严重过敏反应史的人禁用甲型肝炎疫苗。由于甲型肝炎疫苗是灭活产品，对免疫功能低下者接种无需采取特殊预防措施。目前尚无关于孕妇接种甲型肝炎疫苗的数据，但由于它不是活疫苗，对母亲和胎儿的风险应极低或不存在。
