Impact of the introduction of pneumococcal conjugate vaccination on pneumonia in The Gambia: population-based surveillance and case-control studies
Impact of the introduction of pneumococcal conjugate vaccination on pneumonia in The Gambia: population-based surveillance and case-control studies
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DOI：
10.1016/s1473-3099(17)30321-3
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发表时间：
2017-09-01
影响因子：
56.3
通讯作者：
Corrah, Tumani
中科院分区：
文献类型：
--
作者：
Mackenzie, Grant A.;Hill, Philip C.;Corrah, Tumani
背景肺炎球菌结合疫苗（PCVs）在许多低收入国家使用，但其对肺炎发病率的影响尚不清楚。冈比亚于2009年8月推出了PCV7，并于2011年5月推出了PCV13。我们的目的是衡量引入这些疫苗对肺炎发病率的影响。方法进行基于人群的监测和病例对照研究。主要终点是who定义的伴有肺实变的放射性肺炎。对2008年5月12日至2015年12月31日期间2-59月龄儿童（病例对照研究中最小年龄为3月龄）的疑似肺炎进行基于人群的监测。影响研究的监测仅限于Basse健康和人口监测系统（BHDSS），而病例对照研究的监测包括BHDSS和富拉都西部健康和人口监测系统。护士使用转诊给Basse和Bansang临床医生的标准化标准对监测区内所有卫生设施的所有门诊和住院病人进行了筛查。这些临床医生记录临床表现并应用标准化标准来识别疑似肺炎患者。我们比较了基线期（2008年5月12日至2010年5月11日）和PCV13期（2014年1月1日至2015年12月31日）的肺炎发病率。在2011年9月12日至2014年9月31日期间，我们还采用病例对照法调查了PCV13的有效性。对照组年龄在90天或以上，并且有资格接受至少一剂PCV13；病例具有相同的资格标准，并增加了世卫组织定义的放射性肺炎。结果对临床肺炎患儿18 833例进行调查，发现放射性肺炎2156例。在2-11个月大的儿童中，放射性肺炎的发病率从基线期的每1000人年21.0例下降到2014- 2015年的每1000人年16.2例（下降23%，95% CI 7-36）。在12-23个月的年龄组中，放射性肺炎从每1000人年15.3例下降到10.9例（下降29%，12-42）。在2-4岁儿童中，发病率从每1000人年5.2例下降到4.1例（下降22%，1-39）。所有临床肺炎的发病率增加了4%(-1 ~ 8)，但住院病例下降了8%（3 ~ 13）。2-11月龄儿童肺炎球菌肺炎从2.9例/ 1000人年降至1.2例/ 1000人年（下降58%，22-77），12-23月龄儿童肺炎球菌肺炎从2.6例/ 1000人年降至0.7例/ 1000人年（下降75%，47-88）。2-11月龄儿童缺氧肺炎从13.1例/ 1000人年降至5.7例/ 1000人年（下降57%，42-67），12-23月龄儿童缺氧肺炎从6.8例/ 1000人年降至1.9例/ 1000人年（下降72%，58-82）。在病例对照研究中，对于3-11月龄儿童，三剂PCV13预防放射性肺炎的最佳估计是校正优势比为0.57(0.30-1.08)，并且疫苗的有效性随着剂量的增加而增加（p=0.026）。对12个月及以上儿童的分析力度不足，因为很少有未接种疫苗的病例和对照。冈比亚引入PCV对放射性肺炎的发病率产生了中等影响，住院肺炎病例略有减少，幼儿肺炎球菌和缺氧肺炎的发病率大幅下降。采用PCV13并进行合理覆盖的低收入国家可预期住院肺炎病例略有减少，并对严重儿童肺炎的发病率产生显著影响。版权(C)作者(s)。Elsevier Ltd.出版。这是一篇基于CC BY-NC-ND 4.0许可的开放获取文章。
Background Pneumococcal conjugate vaccines (PCVs) are used in many low-income countries but their impact on the incidence of pneumonia is unclear. The Gambia introduced PCV7 in August, 2009, and PCV13 in May, 2011. We aimed to measure the impact of the introduction of these vaccines on pneumonia incidence.Methods We did population-based surveillance and case-control studies. The primary endpoint was WHO-defined radiological pneumonia with pulmonary consolidation. Population-based surveillance was for suspected pneumonia in children aged 2-59 months (minimum age 3 months in the case-control study) between May 12, 2008, and Dec 31, 2015. Surveillance for the impact study was limited to the Basse Health and Demographic Surveillance System (BHDSS), whereas surveillance for the case-control study included both the BHDSS and Fuladu West Health and Demographic Surveillance System. Nurses screened all outpatients and inpatients at all health facilities in the surveillance area using standardised criteria for referral to clinicians in Basse and Bansang. These clinicians recorded clinical findings and applied standardised criteria to identify patients with suspected pneumonia. We compared the incidence of pneumonia during the baseline period (May 12, 2008, to May 11, 2010) and the PCV13 period (Jan 1, 2014, to Dec 31, 2015). We also investigated the effectiveness of PCV13 using case-control methods between Sept 12, 2011, and Sept 31, 2014. Controls were aged 90 days or older, and were eligible to have received at least one dose of PCV13; cases had the same eligibility criteria with the addition of having WHO-defined radiological pneumonia.Findings We investigated 18 833 children with clinical pneumonia and identified 2156 cases of radiological pneumonia. Among children aged 2-11 months, the incidence of radiological pneumonia fell from 21.0 cases per 1000 person-years in the baseline period to 16.2 cases per 1000 person-years (23% decline, 95% CI 7-36) in 2014-15. In the 12-23 month age group, radiological pneumonia decreased from 15.3 to 10.9 cases per 1000 person-years (29% decline, 12-42). In children aged 2-4 years, incidence fell from 5.2 to 4.1 cases per 1000 person-years (22% decline, 1-39). Incidence of all clinical pneumonia increased by 4% (-1 to 8), but hospitalised cases declined by 8% (3-13). Pneumococcal pneumonia declined from 2.9 to 1.2 cases per 1000 person-years (58% decline, 22-77) in children aged 2-11 months and from 2.6 to 0.7 cases per 1000 person-years (75% decline, 47-88) in children aged 12-23 months. Hypoxic pneumonia fell from 13.1 to 5.7 cases per 1000 person-years (57% decline, 42-67) in children aged 2-11 months and from 6.8 to 1.9 cases per 1000 person-years (72% decline, 58-82) in children aged 12-23 months. In the case-control study, the best estimate of the effectiveness of three doses of PCV13 against radiological pneumonia was an adjusted odds ratio of 0.57 (0.30-1.08) in children aged 3-11 months and vaccine effectiveness increased with greater numbers of doses (p=0.026). The analysis in children aged 12 months and older was underpowered because there were few unvaccinated cases and controls.Interpretation The introduction of PCV in The Gambia was associated with a moderate impact on the incidence of radiological pneumonia, a small reduction in cases of hospitalised pneumonia, and substantial reductions of pneumococcal and hypoxic pneumonia in young children. Low-income countries that introduce PCV13 with reasonable coverage can expect modest reductions in hospitalised cases of pneumonia and a marked impact on the incidence of severe childhood pneumonia. Copyright (C) The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license.