Effect of 2 Versus 3 Pneumococcal Conjugate Vaccinations Prevnar on Nasopharyngeal Carriage, Transmission and Herd-immunity;a Randomized, Controlled Study
试验速览
- 阶段
- 3 期
- 状态
- 已完成
- 发起方
- UMC Utrecht
- 入组人数
- 1,005
- 主要终点
- Nasopharyngeal bacterial (pneumococcal) colonization at 6 weeks, 6, 12, 18 and 24 months in infants and at 12 and 24 months of family members
研究概览
简要总结
Two( 2) or three (3) instead of four vaccinations before the age of 6 months with pneumococcal conjugate vaccine are presumed to protect children against invasive pneumococcal disease like meningitis, at least on the short term till 18-24 months of age. The current hypothesis in this study is 2 or 3 vaccinations will protect against IPD but will not alter pneumococcal nasopharyngeal carriage in infants, and consequently not change pneumococcal transmission and induce no herd-immunity. Furthermore, antibody development and memory may benefit from carriage of vaccine type S. pneumoniae
详细描述
Two(2 and 4 months) and three vaccinations (2,4 and 11 months) with 7-valent pneumococcal conjugate vaccine Prevnar in infants are presumed to provide about 90% protection against invasive pneumococcal disease (IPD) for vaccine type pneumococci, at least until 18-24 months of age. Licensure of the vaccine however is based on studies with 3 vaccinations before 6 months and a booster vaccination half a year later (3+1 scheme). Cost-effectiveness in national infant vaccination programs (NIPs)is much improved by high herd-immunity effects,as observed in the USA after licensure of Prevnar in 2000, both for IPD and AOM. However, overall pneumococcal carriage reduction (and nasopharyngeal replacement) has not been assessed in studies with reduced doses. With reduced carriage reduction, effects on respiratory tract infections and herd immunity may be significantly less.
The primary aim of the current study is to compare effect of 2-doses (at ages 2 and 4 months) with a 3-doses scheme(2+1, at 2, 4 and 11 months) on nasopharyngeal pneumococcal carriage and replacement and family transmission(sibs and caregivers), in order to allow modelling for herd-immunity.
The secondary aim is to determine the effect of a reduced doses scheme on serum antipneumococcal antibody levels at the age of 12 and 24 months.
A third aim is to determine antipneumococcal antibody levels and memory B-cell development after booster vaccination at 24 months of age, after 2 or 2+1 doses and compare these with a first vaccination at 24 months of age.
Opportunities are the determination of nasopharyngeal colonizing pneumococci in unvaccinated infants in the Netherlands before implementation of Prevnar in the NIP, evaluation of replacing pneumococci in the nasopharynx after vaccinations and analysis of effects on other colonizing bacteria like H.influenzae, M. catarrhalis and S.aureus. Furthermore, the relation between colonizing pneumococci and serotypes causing IPD in the Netherlands can be evaluated.
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
- Single (Outcomes Assessor)
入排标准
- 年龄范围
- 2 Months 至 3 Months（Child）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Newborn infants eligible for participation in the national infant vaccination program in the Netherlands
排除标准
- •exclusion from the national vaccination program because of the presence of
- •a medical condition requiring treatment that can interfere with the effect of vaccinations
- •known or suspected allergy to components of the pneumococcal conjugate vaccine
- •known or suspected immunodeficiency disease
- •previous treatment with plasma or immunoglobulins
- •previous vaccinations other than hepatitis B vaccinations
- •coagulation disorders
结局指标
主要结局
Nasopharyngeal bacterial (pneumococcal) colonization at 6 weeks, 6, 12, 18 and 24 months in infants and at 12 and 24 months of family members
时间窗: duration of study, 23 months per subject
transmission to family members( sib, caregiver)
时间窗: at infants age of 12 and 24 months
次要结局
- anti-pneumococcal antibody levels at 12 and 24 months of age(23 months)
- antibody levels and B-memory cells after vaccination at 24 months(23 months)