尼日利亚循环疫苗衍生脊髓灰质炎病毒的影响。

Implications of a circulating vaccine-derived poliovirus in Nigeria.

机构信息

Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, United Kingdom.

出版信息

N Engl J Med. 2010 Jun 24;362(25):2360-9. doi: 10.1056/NEJMoa0910074.

DOI:10.1056/NEJMoa0910074

PMID:20573924

Abstract

BACKGROUND

The largest recorded outbreak of a circulating vaccine-derived poliovirus (cVDPV), detected in Nigeria, provides a unique opportunity to analyze the pathogenicity of the virus, the clinical severity of the disease, and the effectiveness of control measures for cVDPVs as compared with wild-type poliovirus (WPV).

METHODS

We identified cases of acute flaccid paralysis associated with fecal excretion of type 2 cVDPV, type 1 WPV, or type 3 WPV reported in Nigeria through routine surveillance from January 1, 2005, through June 30, 2009. The clinical characteristics of these cases, the clinical attack rates for each virus, and the effectiveness of oral polio vaccines in preventing paralysis from each virus were compared.

RESULTS

No significant differences were found in the clinical severity of paralysis among the 278 cases of type 2 cVDPV, the 2323 cases of type 1 WPV, and the 1059 cases of type 3 WPV. The estimated average annual clinical attack rates of type 1 WPV, type 2 cVDPV, and type 3 WPV per 100,000 susceptible children under 5 years of age were 6.8 (95% confidence interval [CI], 5.9 to 7.7), 2.7 (95% CI, 1.9 to 3.6), and 4.0 (95% CI, 3.4 to 4.7), respectively. The estimated effectiveness of trivalent oral polio vaccine against paralysis from type 2 cVDPV was 38% (95% CI, 15 to 54%) per dose, which was substantially higher than that against paralysis from type 1 WPV (13%; 95% CI, 8 to 18%), or type 3 WPV (20%; 95% CI, 12 to 26%). The more frequent use of serotype 1 and serotype 3 monovalent oral polio vaccines has resulted in improvements in vaccine-induced population immunity against these serotypes and in declines in immunity to type 2 cVDPV.

CONCLUSIONS

The attack rate and severity of disease associated with the recent cVDPV identified in Nigeria are similar to those associated with WPV. International planning for the management of the risk of WPV, both before and after eradication, must include scenarios in which equally virulent and pathogenic cVDPVs could emerge.

摘要

背景

在尼日利亚发现的有记录以来最大规模的循环疫苗衍生脊髓灰质炎病毒（cVDPV）爆发，为分析病毒的致病性、疾病的临床严重程度以及 cVDPV 与野生型脊髓灰质炎病毒（WPV）相比的控制措施的效果提供了一个独特的机会。

方法

我们通过 2005 年 1 月 1 日至 2009 年 6 月 30 日的常规监测，确定了尼日利亚报告的与粪便中排出的 2 型 cVDPV、1 型 WPV 或 3 型 WPV 相关的急性弛缓性麻痹病例。比较了这些病例的临床特征、每种病毒的临床攻击率以及口服脊髓灰质炎疫苗预防每种病毒引起的麻痹的效果。

结果

278 例 2 型 cVDPV、2323 例 1 型 WPV 和 1059 例 3 型 WPV 病例的麻痹临床严重程度无显著差异。估计每 10 万名 5 岁以下易感儿童中，1 型 WPV、2 型 cVDPV 和 3 型 WPV 的年均临床攻击率分别为 6.8（95%置信区间[CI]，5.9 至 7.7）、2.7（95%CI，1.9 至 3.6）和 4.0（95%CI，3.4 至 4.7）。三价口服脊髓灰质炎疫苗对 2 型 cVDPV 引起的麻痹的估计有效性为 38%（95%CI，15 至 54%），这明显高于对 1 型 WPV（13%；95%CI，8 至 18%）或 3 型 WPV（20%；95%CI，12 至 26%）引起的麻痹。更频繁地使用 1 型和 3 型单价口服脊髓灰质炎疫苗，提高了疫苗诱导的针对这些血清型的人群免疫力，并降低了对 2 型 cVDPV 的免疫力。