疫苗引入三年后，单价轮状病毒疫苗在马拉维城市儿童中的人群影响及效果：生态学和病例对照分析
Population Impact and Effectiveness of Monovalent Rotavirus Vaccination in Urban Malawian Children 3 Years After Vaccine Introduction: Ecological and Case-Control Analyses.
作者信息
Bar-Zeev Naor, Jere Khuzwayo C, Bennett Aisleen, Pollock Louisa, Tate Jacqueline E, Nakagomi Osamu, Iturriza-Gomara Miren, Costello Anthony, Mwansambo Charles, Parashar Umesh D, Heyderman Robert S, French Neil, Cunliffe Nigel A
机构信息
Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre Institute of Infection and Global Health, University of Liverpool, United Kingdom.
Epidemiology Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
出版信息
Clin Infect Dis. 2016 May 1;62 Suppl 2(Suppl 2):S213-9. doi: 10.1093/cid/civ1183.
BACKGROUND
Rotavirus vaccines have been introduced in many low-income African countries including Malawi in 2012. Despite early evidence of vaccine impact, determining persistence of protection beyond infancy, the utility of the vaccine against specific rotavirus genotypes, and effectiveness in vulnerable subgroups is important.
METHODS
We compared rotavirus prevalence in diarrheal stool and hospitalization incidence before and following rotavirus vaccine introduction in Malawi. Using case-control analysis, we derived vaccine effectiveness (VE) in the second year of life and for human immunodeficiency virus (HIV)-exposed and stunted children.
RESULTS
Rotavirus prevalence declined concurrent with increasing vaccine coverage, and in 2015 was 24% compared with prevaccine mean baseline in 1997-2011 of 32%. Since vaccine introduction, population rotavirus hospitalization incidence declined in infants by 54.2% (95% confidence interval [CI], 32.8-68.8), but did not fall in older children. Comparing 241 rotavirus cases with 692 test-negative controls, VE was 70.6% (95% CI, 33.6%-87.0%) and 31.7% (95% CI, -140.6% to 80.6%) in the first and second year of life, respectively, whereas mean age of rotavirus cases increased from 9.3 to 11.8 months. Despite higher VE against G1P[8] than against other genotypes, no resurgence of nonvaccine genotypes has occurred. VE did not differ significantly by nutritional status (78.1% [95% CI, 5.6%-94.9%] in 257 well-nourished and 27.8% [95% CI, -99.5% to 73.9%] in 205 stunted children;P= .12), or by HIV exposure (60.5% [95% CI, 13.3%-82.0%] in 745 HIV-unexposed and 42.2% [95% CI, -106.9% to 83.8%] in 174 exposed children;P= .91).
CONCLUSIONS
Rotavirus vaccination in Malawi has resulted in reductions in disease burden in infants <12 months, but not in older children. Despite differences in genotype-specific VE, no genotype has emerged to suggest vaccine escape. VE was not demonstrably affected by HIV exposure or stunting.
背景
包括马拉维在内的许多低收入非洲国家于2012年引入了轮状病毒疫苗。尽管有早期证据表明疫苗有影响，但确定婴儿期之后保护作用的持续性、疫苗对特定轮状病毒基因型的效用以及在脆弱亚组中的有效性很重要。
方法
我们比较了马拉维引入轮状病毒疫苗前后腹泻粪便中轮状病毒的流行率和住院发病率。通过病例对照分析，我们得出了生命第二年以及暴露于人类免疫缺陷病毒（HIV）的儿童和发育迟缓儿童的疫苗效力（VE）。
结果
轮状病毒流行率随着疫苗覆盖率的增加而下降，2015年为24%，而1997 - 2011年疫苗接种前的平均基线为32%。自引入疫苗以来，婴儿中轮状病毒住院发病率下降了54.2%（95%置信区间[CI]，32.8 - 68.8），但大龄儿童中并未下降。将241例轮状病毒病例与692例检测阴性对照进行比较，生命第一年和第二年的疫苗效力分别为70.6%（95% CI，33.6% - 87.0%）和31.7%（95% CI， - 140.6%至80.6%），而轮状病毒病例的平均年龄从9.3个月增加到11.8个月。尽管针对G1P[8]的疫苗效力高于其他基因型，但未出现非疫苗基因型的回升。疫苗效力在营养状况方面无显著差异（257名营养良好儿童中为78.1%[95% CI，5.6% - 94.9%]，205名发育迟缓儿童中为27.8%[95% CI， - 99.5%至73.9%]；P = 0.12），在HIV暴露方面也无显著差异（745名未暴露于HIV的儿童中为60.5%[95% CI，13.3% - 82.0%]，174名暴露儿童中为42.2%[95% CI， - 106.9%至83.8%]；P = 0.91）。
结论
马拉维的轮状病毒疫苗接种已使12个月以下婴儿的疾病负担减轻，但大龄儿童未减轻。尽管基因型特异性疫苗效力存在差异，但未出现表明疫苗逃逸的基因型。疫苗效力未受到HIV暴露或发育迟缓的明显影响。
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