Prevention of Cytomegalovirus Infection

描述(申请人提供)：胎儿感染巨细胞病毒(CMV)导致每年约8,000名婴儿出生，他们将成为智障和/或聋人。这些影响主要是由于母亲在怀孕期间感染了CMV。我们和其他人发现，25%到80%的儿童在托儿所感染CMV，并在3到41个月(平均18个月)内脱离病毒。在两岁以下孩子感染的母亲中，至少有一半在一年内从孩子身上感染了巨细胞病毒，而在其他血清阴性的妇女中，这一比例为每年5%。有可能控制这种感染的CMV疫苗可供评估。预防孕期初级孕产妇感染的有效国家疫苗接种战略应包括儿童免疫接种。在成年人中，我们发现自然的血清阳性可以防止再次感染。为了确定中和抗体对幼儿CMV感染自然病史的影响，我们将在扩大的安慰剂对照双盲I-II期安全性和免疫原性试验中评估纯化蛋白疫苗CMV GB/MF59。由于这项研究中的婴儿将被登记在日间托儿所，并且有很高的原发CMV感染率，我们将检验以下假设：接种疫苗的两岁以下儿童免受感染或病毒排泄持续时间缩短，其中之一将与高水平的中和抗体有关。我们将比较在托儿所登记并接种CMV GB/MF59疫苗的两岁以下婴儿的感染率和病毒排泄持续时间，与接受安慰剂的匹配血清阴性婴儿的感染率和病毒排泄持续时间进行比较。我们还将确定感染或病毒脱落的持续时间是否与婴儿的免疫反应或年龄有关。要测量的免疫反应参数将包括免疫球蛋白、巨细胞病毒gB的免疫球蛋白、中和滴度、以免疫印迹为特征的免疫球蛋白应答、CD4+应答细胞频率和粘膜免疫。这项研究的结果将确定是否有可能预防CMV感染。

DESCRIPTION (provided by applicant): Infection of the fetus with cytomegalovirus (CMV) results in approximately 8,000 infants born each year who will be mentally retarded and/or deaf. These effects are mainly due to primary maternal CMV infection during pregnancy. We and others have found that between 25% and 80% of children acquire CMV infections in daycare and shed the virus for between 3 and 41 months (mean of 18 months). At least half of seronegative mothers with infected children under age 2 years acquire CMV from their children within one year compared to an annual rate of < 5% among other seronegative women. CMV vaccines with the potential to control this infection are available for evaluation. An effective national vaccination strategy to prevent primary maternal infection during pregnancy should include childhood immunization. In adults we found that natural seropositivity protects against reinfections. To determine neutralizing antibodies are effect the natural history of CMV infection in toddlers, we will evaluate a purified protein vaccine, CMV gB/MF59, in an expanded placebo controlled double blinded phase I-II safety and immunogenicity trial. Because the infants in this study will be enrolled in daycare and will have a high rate of primary CMV infections we will be testing the hypothesis that immunized children less than two years of age are protected against infection or have a reduced duration of viral excretion and one or the other of these will be associated with high levels of neutralizing antibodies. We will compare the infection rate or the duration of viral excretion of infants under two years of age enrolled in daycare and immunized with CMV gB/MF59 vaccine to the infection rate and duration of viral excretion of matched seronegative infants receiving a placebo. We will also determine if infection or the duration of viral shedding are associated with an infant's immune response or age. The parameters of the immune response to be measured will include IgG, IgG to CMV gB, neutralizing titers, IgG responses characterized by immunoblotting, CD4+ responder cell frequencies, and mucosal immunity. The results of this study will establish if prevention of CMV infections is possible.