Richtmann R, Chaves R L, Mendonça J S, Konichi S R, Mitre H P, Takei K, Dietz K, Flehmig B
Department of Infectious Diseases, Hospital do Servidor Publico Estadual Franciso Morato de Oliveira, São Paulo, Brazil.
J Med Virol. 1996 Feb;48(2):147-50. doi: 10.1002/(SICI)1096-9071(199602)48:2<147::AID-JMV5>3.0.CO;2-9.
The objective of this study was to characterize the immune response of children after the use of two different vaccine doses and to evaluate whether vaccination benefits children attending day care centers in areas with high anti-HAV seroprevalence. The study was conducted in a day care center with a stable population in São Paulo, Brazil. Two groups of 20 children, all seronegative for hepatitis A antibodies, were assigned randomly to receive three times 0.5 and 1.0 ml of the vaccine, the second and third dose 1 and 6 months after the first dose, respectively. There were 27 children in the control group. All children in both vaccinated groups had protective levels of antibodies in the serum after two inoculations, and serious adverse reactions were not observed. In the eighth month of follow-up, a hepatitis A outbreak occurred in the day care center. Five children in the control group had high titers of IgM class anti-HAV, four with clinical manifestations of acute hepatitis. None of the vaccinated children developed symptoms or signs of hepatitis (P = 0.0125), and the estimate of vaccine efficacy was 100%. Two nonstudy children from the center also had clinical and serological evidence of acute hepatitis A. It is concluded that vaccination represents an important method for prevention of hepatitis A transmission in day care centers. The results of this pilot study justify further testing in larger groups.
本研究的目的是描述儿童在使用两种不同疫苗剂量后的免疫反应，并评估在甲型肝炎血清流行率高的地区，接种疫苗对日间护理中心儿童是否有益。该研究在巴西圣保罗一个人口稳定的日间护理中心进行。两组各20名甲型肝炎抗体均为血清阴性的儿童被随机分配，分别接受三次0.5毫升和1.0毫升的疫苗接种，第二剂和第三剂分别在第一剂接种后1个月和6个月接种。对照组有27名儿童。两个接种组的所有儿童在两次接种后血清中抗体水平均达到保护水平，且未观察到严重不良反应。在随访的第八个月，日间护理中心发生了甲型肝炎疫情。对照组有5名儿童甲型肝炎IgM抗体滴度高，其中4名有急性肝炎的临床表现。接种疫苗的儿童均未出现肝炎症状或体征（P = 0.0125），疫苗效力估计为100%。该中心两名非研究儿童也有甲型肝炎急性感染的临床和血清学证据。结论是，接种疫苗是预防日间护理中心甲型肝炎传播的重要方法。这项初步研究的结果证明有必要在更大规模的人群中进一步试验。
