Assessing Immunogenicity of Measles-Rubella Vaccine at 6 and 9 Months of Age
试验速览
- 阶段
- 4 期
- 状态
- 已完成
- 入组人数
- 637
- 试验地点
- 1
- 主要终点
- Percent of Infants Who Were Seropositive After Immunization at 6 Months (Assessed at 9-month Visit)
研究概览
简要总结
This is an open-label, randomized, 2-arm clinical trial in healthy infants in Bangladesh. The primary purpose of the study is to assess the immunogenicity of measles-rubella (MR) vaccine when delivered at 6 months. In addition, the study will establish the equality of MR vaccine seroconversion administered at 9 months following administration of an earlier MR vaccine dose at 6 months of age compared to MR vaccine dose administered at 9 months without previous MR vaccination. This study will also provide additional data on safety and tolerance of MR vaccine given at 6 months, and impact of maternal antibodies on immunogenicity of MR vaccine at 6 months.
- Primary objectives:
- To assess immunogenicity of MR vaccine at 6 months of age
- To assess immunogenicity of MR vaccine at 9 months of age among children without prior measles and rubella vaccination, compared with MR vaccine immunogenicity among those who had a prior MR vaccination at 6 months of age
- Secondary objectives
- To assess the frequency of adverse reactions following administration of MR vaccine at 6 months
- To compare the immunogenicity of the MR vaccine first dose administered at 6 months vs at 9 months.
- To assess the proportion of mothers with undetectable, detectable and protective levels of measles and rubella antibodies
- To determine the extent of variation in measles antibodies in women of child bearing age in a population with a long standing measles vaccination program
- To determine the extent of variation in rubella antibodies in women of child bearing age in a population where rubella vaccine have been recently introduced
- To determine if variation in antibody levels in infants at 6 months is predominately explained by variation in starting antibody levels in the mother in this population
- To estimate the half-life of decay of measles and rubella antibodies in infants
详细描述
In countries with low levels of circulating measles virus, and lower risk for measles infection, measles containing vaccine first dose (MCV1) is recommended at 12 months of age. In countries with high risk for measles, MCV1 is recommended at 9 months. In the past decade, many countries have been experiencing measles outbreaks with a high proportion of cases among infants < 9 months of age, below the recommended age of routine MCV1.
Recent publications suggest that this may be due to the fact that the majority of infants now are born to mothers with vaccine induced immunity to measles, and who lose maternal antibodies much earlier, by age of 4-6 months. For example, in a measles outbreak in Malawi in 2010, 14% (17,858) of the estimated 134,000 cases occurred in children 0-8 months. In 2013, in a measles outbreak in Sri Lanka approximately 34% of measles cases were in children 6-12 months of age. Furthermore, in 2013 Jordan experienced a large measles outbreak with high proportion of young infants affected (6-9 months). WHO measles outbreak response guidelines recommend vaccinating children as young as 6 months during outbreaks. As an example, in response to a measles outbreak, Sri Lanka and Jordan conducted outbreak response immunization (ORI) that included infants 6 months of age despite the limited evidence on immunogenicity of MR vaccine at that age.
Some researchers suggest that routine MCV should be given before age of 9 months based on published data showing that infants born to mothers with vaccine induced measles immunity are born with lower concentration of maternal measles antibodies (MMA) and lose protection against measles infection at an earlier age. Measles vaccine immunogenicity depends on several factors, including presence of maternal measles antibodies (i.e., passively acquired measles antibodies may neutralize vaccine virus before a complete immune response develops resulting in primary vaccine failure.), maturity of immune system of the vaccine recipient, and strain of the measles vaccine used. So any decisions to alter the age of MCV1 dose should balance the potential risk of primary vaccine failure against the risk of measles infection and measles related complications, including death. Immunogenicity of measles vaccine given at 6 months is well studied; however, data on immunogenicity of combined MR vaccine administered at 6 months and its impact on MR vaccine effectiveness given at 9 months, is limited.
Because the number of infants born to mothers with vaccine induced immunity has been steadily increasing and most countries will be using MR vaccine routinely in the Expanded Program of Immunization (EPI), it is timely to conduct a study to assess immunogenicity of MR vaccine given at 6 months and its impact on a subsequent 9 month MR dose. The first dose of MCV given at 6 months is frequently referred to as MCV-0, indicating that two subsequent doses are needed to attain population seroprotection levels necessary to stop endemic transmission of the measles virus.
To improve the accuracy of interpretation of study results blood samples of mothers of enrolled infants will be tested for measles and rubella antibodies. This will also enable us to determine the proportion of mothers with undetectable, detectable and protective levels of antibodies, and to assess the relationship between the level of antibodies in mothers and their infants' maternal antibodies.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- None
盲法说明
Open label
入排标准
- 年龄范围
- 173 Days 至 187 Days（Child）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy infants at 6 months (180 days, +/- 7 days) of age
- •A parent or guardian that consents for participation in the full length of the study
- •A parent or guardian that is able to understand and comply with planned study procedures
- •Inclusion criteria: MOTHERS:
- •Mothers of infants that meet inclusion criteria.
- •≥18 years of age
- •Mothers who consent to participate in the full length of the study
排除标准
- •Family that is unable to participate in the full length of the study
- •A diagnosis or suspicion of immunodeficiency disorder either in the infant or mother
- •A diagnosis or suspicion of bleeding disorder that would contraindicate parenteral administration of MR vaccine or collection of blood by venipuncture
- •Acute infection or illness at the time of enrollment (6 months) that would require infant's admission to a hospital
- •Receipt of any measles or rubella containing vaccine prior to enrolment (i.e., before age 6 months) outside of study based upon documentation or parental recall
- •Known history of laboratory confirmed measles or rubella infection
- •A diagnosis of rubella infection in mother during pregnancy
- •A diagnosis of congenital rubella syndrome in infant
- •Known allergy/sensitivity or reaction to measles-rubella containing vaccine or contents of measles-rubella containing vaccine
- •Persons with a history of an anaphylactic reaction to any components of the vaccine
- •Infants from premature births (<37 weeks of gestation)
- •Exclusion criteria: MOTHERS:
- •Refuses to give blood samples. (If the mother agrees for her child to participate in the study, but refuses to give a blood samples herself or blood samples cannot be obtained, the child will still be enrolled.)
- •A diagnosis or suspicion of immunodeficiency disorder
- •A diagnosis or suspicion of bleeding disorder that would contraindicate collection of blood by venipuncture
- •Temporary exclusion: INFANTS:
- •Acute febrile illness (≥38°C) at the time of enrollment
- •Family will be requested to bring back the child 1-2 days later or when child feels better.
研究组 & 干预措施
Group A: early dose
Infants receive a measles-rubella vaccine at 6 and 9 months. Infants receive a standard dose according to the vaccine package insert each time. (Mothers receive no intervention.)
干预措施: Measles-rubella (MR) vaccine at 6 months of age (Biological)
Group A: early dose
Infants receive a measles-rubella vaccine at 6 and 9 months. Infants receive a standard dose according to the vaccine package insert each time. (Mothers receive no intervention.)
干预措施: Measles-rubella (MR) vaccine at 9 months of age (Biological)
Group B: standard dose
Infants receive a measles-rubella vaccine at 9 months only. Infants receive a standard dose according to the vaccine package insert. (Mothers receive no intervention.)
干预措施: Measles-rubella (MR) vaccine at 9 months of age (Biological)
结局指标
主要结局
Percent of Infants Who Were Seropositive After Immunization at 6 Months (Assessed at 9-month Visit)
时间窗: Infant antibody titer at 9 months.
# seropositive infants at 9 months/ # of infants in the arm Measles neutralizing antibody titers as measured by plaque reduction neutralization assay is defined as seropositive at ≥ 120 mIU/mL. Rubella antibody titers as measured by ELISA are considered seropositive at \>10 IU/mL. Abbreviations mIU =milli-International unit; IU International units; mL milliliter
Percent of Infants Who Were Seropositive After Immunization at 9 Months (Assessed at 11-month Visit)
时间窗: Infant antibody titer at 11 months.
# seropositive at 11 months of age/ # of infants in the arm \* 100 Measles neutralizing antibody titers as measured by plaque reduction neutralization assay is defined as seropositive at ≥ 120 mIU/mL. Rubella antibody titers as measured by ELISA are considered seropositive at \>10 IU/mL. Abbreviations mIU =milli-International unit; IU International units; mL milliliter
次要结局
- Adverse Effects Following Immunization (AEFI) at the Age of 6 Months(0-30 minutes; 48-hour visit.)
- Immunogenicity at 9 Months - Measles(At 9 months and 11 months of age)
- Immunogenicity at 9 Months - Rubella(At 9 months and 11 months of age)
- Measles and Rubella Titers of Enrolled Mothers(Baseline enrollment (when infant was 6 months of age))
- Pearson Correlation Coefficient of Infant Measles and Rubella Antibody Levels at 6, 9, and 11 Months of Age Compared to Maternal Antibody Levels at Baseline (a Proxy for Infant Antibody Levels at Birth).(baseline (6 months infant age); 2nd blood draw (9 months of age) and 3rd blood draw (at 11 months of age))
- Half-life and Decay of Maternal Measles and Rubella Antibodies.(Day 1 to day 84)
研究者
Jennifer Knapp
Epidemiologist
Centers for Disease Control and Prevention