在巴布亚新几内亚，3至5岁的儿童在婴儿期接种过肺炎球菌多糖疫苗（无论之前是否接种过肺炎球菌结合疫苗）或未接种过肺炎球菌疫苗，其对肺炎球菌的反应相似。
Pneumococcal responses are similar in Papua New Guinean children aged 3-5 years vaccinated in infancy with pneumococcal polysaccharide vaccine with or without prior pneumococcal conjugate vaccine, or without pneumococcal vaccination.
作者信息
van den Biggelaar Anita H J, Richmond Peter C, Fuery Angela, Anderson Denise, Opa Christine, Saleu Gerard, Lai Mildred, Francis Jacinta P, Alpers Michael P, Pomat William S, Lehmann Deborah
机构信息
Telethon Kids Institute, University of Western Australia, Perth, Western Australia, Australia.
School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia.
出版信息
PLoS One. 2017 Oct 13;12(10):e0185877. doi: 10.1371/journal.pone.0185877. eCollection 2017.
TRIAL DESIGN
In an earlier trial, Papua New Guinean (PNG) children at high risk of pneumococcal disease were randomized to receive 0 or 3 doses of 7-valent pneumococcal conjugate vaccine (PCV7), followed by a single dose of 23-valent pneumococcal polysaccharide vaccine (PPV23) at 9 months of age. We here studied in a non-randomized follow-up trial the persistence of pneumococcal immunity in these children at 3-5 years of age (n = 132), and in 121 community controls of a similar age with no prior pneumococcal vaccination.
METHODS
Circulating IgG antibody titers to all PCV7 and PPV23-only serotypes 2, 5 and 7F were measured before and after challenge with 1/5th of a normal PPV23 dose. Serotype-specific memory B-cells were enumerated at 10 months and 3-5 years of age for a subgroup of study children.
RESULTS
Serotype-specific IgG antibody titers before and after challenge were similar for children who received PCV7/PPV23, PPV23 only, or no pneumococcal vaccines. Before challenge, at least 89% and 59% of children in all groups had serotype-specific titers ≥ 0.35μg/ml and ≥ 1.0 μg/ml, respectively. Post-challenge antibody titers were higher or similar to pre-challenge titers for most children independent of pneumococcal vaccination history. The rise in antibody titers was significantly lower when pre-challenge titers were higher. Overall the relative number of serotype-specific memory B-cells remained the same or increased between 10 months and 3-5 years of age, and there were no differences in serotype-specific memory B-cell numbers at 3-5 years of age between the three groups.
CONCLUSIONS
Immunity induced by PCV7 and/or PPV23 immunization in infancy does not exceed that of naturally acquired immunity in 3-5-year-old children living in a highly endemic area. Also, there was no evidence that PPV23 immunization in the first year of life following PCV7 priming induces longer-term hypo-responsiveness.
TRIAL REGISTRATION
Clinicaltrials.gov NCT01414504 and NCT00219401.
试验设计
在一项早期试验中，将肺炎球菌疾病高风险的巴布亚新几内亚（PNG）儿童随机分为两组，分别接受0剂或3剂7价肺炎球菌结合疫苗（PCV7），然后在9月龄时接种1剂23价肺炎球菌多糖疫苗（PPV23）。我们在一项非随机随访试验中研究了这些3至5岁儿童（n = 132）以及121名年龄相仿、未曾接种过肺炎球菌疫苗的社区对照儿童体内肺炎球菌免疫力的持久性。
方法
在使用1/5标准剂量PPV23进行激发前后，检测所有PCV7及仅PPV23所含血清型2、5和7F的循环IgG抗体滴度。对部分研究儿童在10月龄以及3至5岁时进行血清型特异性记忆B细胞计数。
结果
接受PCV7/PPV23、仅PPV23或未接种肺炎球菌疫苗的儿童在激发前后的血清型特异性IgG抗体滴度相似。在激发前，所有组中至少89%和59%的儿童血清型特异性滴度分别≥0.35μg/ml和≥1.0μg/ml。对于大多数儿童，无论肺炎球菌疫苗接种史如何，激发后的抗体滴度均高于或与激发前相似。当激发前滴度较高时，抗体滴度的升高显著降低。总体而言，血清型特异性记忆B细胞的相对数量在10月龄至3至5岁之间保持不变或增加，三组在3至5岁时血清型特异性记忆B细胞数量无差异。
结论
婴儿期PCV7和/或PPV23免疫诱导的免疫力不超过生活在高流行地区的3至5岁儿童自然获得的免疫力。此外，没有证据表明在PCV7初次免疫后的第一年接种PPV23会诱导长期低反应性。
试验注册
Clinicaltrials.gov NCT01414504和NCT00219401。
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