埃塞俄比亚阿姆哈拉州儿童百日咳疫苗保护效力评估
Assessment of Pertussis Vaccine Protective Effectiveness in Children in the Amhara Regional State, Ethiopia.
作者信息
Taye Solomon, Tessema Belay, Gelaw Baye, Moges Feleke
机构信息
Department of Medical Microbiology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, P.O. Box 196, Gondar, Amhara Regional State, Ethiopia.
Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Wachemo University, P.O. Box 667, Hawassa, South Nations Nationalities and Peoples Regional State, Ethiopia.
出版信息
Int J Microbiol. 2020 Oct 13;2020:8845835. doi: 10.1155/2020/8845835. eCollection 2020.
BACKGROUND
is a human pathogen which causes pertussis, or whooping cough. The diphtheria-tetanus-pertussis immunization has significantly reduced the morbidity and mortality of pertussis globally. However, higher prevalence and resurgence of pertussis cases among both vaccinated and unvaccinated people has raised questions on the effectiveness of pertussis vaccine over time. Therefore, the objective of this study was to assess the protective effectiveness of pertussis vaccine in the Amhara Regional State, Ethiopia.
METHODS
A nested matched case-control study design approach was used with vaccinated individuals as cases and unvaccinated individuals as controls. The study was conducted from July 2018 to February 2019. Real-time (RT-) PCR assay was done to ascertain the presence of pertussis among clinically suspected patients. Bivariable and multivariable logistic regression analyses were computed to estimate the crude and adjusted odds ratios (ORs), respectively. Vaccine effectiveness was calculated as (1 - OR) × 100. Adjusted OR with 95% CI and a value <0.05 were used to assess statistical significance.
RESULTS
A total of 112 vaccinated and 223 unvaccinated controls were enrolled for the study. Of the total participants, 173/335 (51.6%) were males. The prevalence of pertussis among vaccinated was 35/112 (31.3%), whereas it was 84/223 (37.7%) among the control group. The adjusted matched vaccine protective effectiveness against infection following three doses of whole-cell vaccine was 25% among children aged between 6 and 9 years. Adjusted estimates of vaccine protective effectiveness for participants who had complete vaccination, stratified by time since last vaccination, were 50% at 6 years, 34% at 7 years, and 2% at 8-9 years since last vaccination.
CONCLUSION
Despite the availability and good coverage of childhood vaccination, the effectiveness of pertussis vaccine was found to be low in the Amhara region, Ethiopia. Moreover, we observed declining trends in the protective effectiveness of the vaccine after 6 years of vaccination. Thus, by considering the waning nature of immune response which is induced by whole-cell vaccine during early life, booster dose is highly recommended to optimize pertussis prevention and control strategies.
背景
百日咳杆菌是一种引起百日咳的人类病原体。白喉-破伤风-百日咳疫苗接种已在全球范围内显著降低了百日咳的发病率和死亡率。然而，接种疫苗者和未接种疫苗者中百日咳病例的较高流行率和复发情况引发了关于百日咳疫苗长期有效性的疑问。因此，本研究的目的是评估埃塞俄比亚阿姆哈拉州百日咳疫苗的保护效果。
方法
采用巢式匹配病例对照研究设计方法，将接种疫苗的个体作为病例，未接种疫苗的个体作为对照。研究于2018年7月至2019年2月进行。对临床疑似患者进行实时（RT-）PCR检测以确定是否存在百日咳杆菌。进行二元和多变量逻辑回归分析，分别估计粗比值比（OR）和调整后的比值比。疫苗效力计算为（1 - OR）×100。使用95%置信区间的调整后OR和P值<0.05来评估统计学意义。
结果
本研究共纳入112名接种疫苗的病例和223名未接种疫苗的对照。在所有参与者中，173/335（51.6%）为男性。接种疫苗者中百日咳的患病率为35/112（31.3%），而对照组中为84/223（37.7%）。在6至9岁儿童中，三剂全细胞疫苗接种后针对百日咳杆菌感染的调整后匹配疫苗保护效力为25%。按最后一次接种疫苗后的时间分层，对完成全程接种的参与者的疫苗保护效力调整估计值为：最后一次接种疫苗后6年时为50%，7年时为34%，8至9年时为2%。
结论
尽管有儿童疫苗且接种覆盖率良好，但在埃塞俄比亚阿姆哈拉地区发现百日咳疫苗的效力较低。此外，我们观察到接种疫苗6年后疫苗保护效力呈下降趋势。因此，考虑到全细胞疫苗在生命早期诱导的免疫反应的衰减特性，强烈建议接种加强剂量以优化百日咳预防和控制策略。
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