Predicting the impact of vaccination on the transmission dynamics of typhoid in South Asia: a mathematical modeling study.
Predicting the impact of vaccination on the transmission dynamics of typhoid in South Asia: a mathematical modeling study.
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预测疫苗接种对南亚伤寒传播动态的影响：一项数学模型研究。
DOI：
10.1371/journal.pntd.0002642
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发表时间：
2014
影响因子：
3.8
通讯作者：
Grenfell BT
中科院分区：
文献类型：
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作者：
Pitzer VE;Bowles CC;Baker S;Kang G;Balaji V;Farrar JJ;Grenfell BT
通过对伤寒传播动态进行建模，可以评估疫苗接种的潜在直接和间接影响；然而，基于数据的相关伤寒模型很少被采用。我们开发了一个简约的年龄结构模型，描述了伤寒感染的自然历史和免疫力。该模型适用于2000年至2012年期间在印度韦洛尔基督教医学院医院就诊的经培养确认的伤寒病例的数据。该模型随后被用来评估使用口服活疫苗、Vi-多糖疫苗和Vi结合疫苗的学校疫苗接种策略的潜在影响。该模型能够再现韦洛尔地区伤寒病例的发病率和年龄分布。在此环境下，伤寒的基本繁殖数(R0)估计为2.8。接种疫苗预计会在短期内提供实质性的间接保护，导致伤寒发病率下降，但(直观地)伤寒发病率预计将在一次性运动后5-15年内反弹。我们发现，对疫苗接种的整体和间接影响的模型预测在很大程度上依赖于慢性携带者在传播中的作用。携带者的传播率被初步估计为低，这与最近的研究一致，但被确定为未来研究的关键领域。仅通过接种疫苗不太可能从流行环境中消除伤寒。我们建立了伤寒传播动力学的数学模型，以评估疫苗接种的潜在直接和间接(即群体免疫)效应。该模型符合来自印度韦洛尔的数据，并与集群随机疫苗试验的结果进行了验证。我们评估了各种以学校为基础的疫苗接种策略，发现接种伤寒疫苗有望带来短期的间接保护和伤寒发病率的下降，但仅接种疫苗不太可能导致消除。间接保护的水平被发现取决于对慢性携带者作用的假设，这确定了未来研究的一个重要领域。
Modeling of the transmission dynamics of typhoid allows for an evaluation of the potential direct and indirect effects of vaccination; however, relevant typhoid models rooted in data have rarely been deployed. We developed a parsimonious age-structured model describing the natural history and immunity to typhoid infection. The model was fit to data on culture-confirmed cases of typhoid fever presenting to Christian Medical College hospital in Vellore, India from 2000–2012. The model was then used to evaluate the potential impact of school-based vaccination strategies using live oral, Vi-polysaccharide, and Vi-conjugate vaccines. The model was able to reproduce the incidence and age distribution of typhoid cases in Vellore. The basic reproductive number (R 0) of typhoid was estimated to be 2.8 in this setting. Vaccination was predicted to confer substantial indirect protection leading to a decrease in the incidence of typhoid in the short term, but (intuitively) typhoid incidence was predicted to rebound 5–15 years following a one-time campaign. We found that model predictions for the overall and indirect effects of vaccination depend strongly on the role of chronic carriers in transmission. Carrier transmissibility was tentatively estimated to be low, consistent with recent studies, but was identified as a pivotal area for future research. It is unlikely that typhoid can be eliminated from endemic settings through vaccination alone. We developed a mathematical model for the transmission dynamics of typhoid in order to evaluate the potential direct and indirect (i.e. herd immunity) effects of vaccination. The model was fit to data from Vellore, India and validated against the results of cluster randomized vaccine trials. We evaluated a variety of school-based vaccination strategies and found that typhoid vaccination is expected to lead to short-term indirect protection and a decrease in typhoid incidence, but vaccination alone is unlikely to lead to elimination. The level of indirect protection was found to depend on assumptions about the role of chronic carriers, identifying an important area for future research.
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影响因子：
6.4
作者：
LEVINE, MM;BLACK, RE;LANATA, C
通讯作者：
LANATA, C
影响因子：
168.9
作者：
Lozano, Rafael;Naghavi, Mohsen;Murray, Christopher J. L.
通讯作者：
Murray, Christopher J. L.
影响因子：
4.3
作者：
GONZALEZGUZMAN, J
通讯作者：
GONZALEZGUZMAN, J
影响因子：
7.5
作者：
LANGE, HJ;ULM, K;HUBER, HC
通讯作者：
HUBER, HC
DOI：
10.1038/nrmicro2490
发表时间：
2011-01
期刊：
Nature reviews. Microbiology
影响因子：
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作者：
通讯作者：
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