Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report
Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report
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DOI：
10.1056/nejmoa1710430
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发表时间：
2019-08-01
影响因子：
158.5
通讯作者：
Staples, J. Erin
中科院分区：
文献类型：
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作者：
Casey, Rebecca M.;Harris, Jennifer B.;Staples, J. Erin
2016年，安哥拉和刚果民主共和国对黄热病疫情的应对导致全球黄热病疫苗短缺。因此，在金沙萨的一次先发制人的运动中，向760万2岁或以上儿童和未怀孕的成年人提供了少量17DD黄热病疫苗（含标准剂量的五分之一[0.1毫升]）。本研究的目的是评估在大规模运动中对部分剂量的免疫反应。方法在6个疫苗接种点招募4个年龄层的参与者。我们使用具有50%临界值（PRNT50）的斑块减少中和试验，评估了接种前和接种后1个月和1年获得的血液样本中针对黄热病病毒的中和抗体滴度。PRNT50滴度为10或更高的参与者被认为是血清阳性。基线滴度小于10的患者在随访时呈血清阳性，被归类为进行了血清转化。基线时血清阳性和随访时滴度增加4倍或更多的参与者被归类为有免疫反应。结果在完成1个月随访的716名参与者中，705名（98%；95%可信区间[CI]， 97至99）接种疫苗后血清呈阳性。在493名基线时血清阴性的参与者中，482名（98%;95% CI, 96 - 99）进行了血清转化。在223名基线时血清阳性的参与者中，148名（66%;95% CI, 60 - 72）有免疫应答。较低的基线滴度与较高的免疫应答概率相关(P
Background In 2016, the response to a yellow fever outbreak in Angola and the Democratic Republic of Congo led to a global shortage of yellow fever vaccine. As a result, a fractional dose of the 17DD yellow fever vaccine (containing one fifth [0.1 ml] of the standard dose) was offered to 7.6 million children 2 years of age or older and nonpregnant adults in a preemptive campaign in Kinshasa. The goal of this study was to assess the immune response to the fractional dose in a large-scale campaign. Methods We recruited participants in four age strata at six vaccination sites. We assessed neutralizing antibody titers against yellow fever virus in blood samples obtained before vaccination and at 1 month and 1 year after vaccination, using a plaque reduction neutralization test with a 50% cutoff (PRNT50). Participants with a PRNT50 titer of 10 or higher were considered to be seropositive. Those with a baseline titer of less than 10 who became seropositive at follow-up were classified as having undergone seroconversion. Participants who were seropositive at baseline and who had an increase in the titer by a factor of 4 or more at follow-up were classified as having an immune response. Results Among 716 participants who completed the 1-month follow-up, 705 (98%; 95% confidence interval [CI], 97 to 99) were seropositive after vaccination. Among 493 participants who were seronegative at baseline, 482 (98%; 95% CI, 96 to 99) underwent seroconversion. Among 223 participants who were seropositive at baseline, 148 (66%; 95% CI, 60 to 72) had an immune response. Lower baseline titers were associated with a higher probability of having an immune response (P