Abstract：
BACKGROUND: Mass gatherings can not only trigger major outbreaks on-site but also facilitate global spread of infectious pathogens. Hajj is one of the largest mass gathering events worldwide where over two million pilgrims from all over the world gather annually creating intense congestion.
METHODS: We developed a meta-population model to represent the transmission dynamics of Neisseria meningitidis and the impact of Hajj pilgrimage on the risk of invasive meningococcal disease (IMD) for pilgrims population, local population at the Hajj site and country of origin of Hajj pilgrims. This model was calibrated using data on IMD over 17 years (1995-2011) and further used to simulate potential changes in vaccine policy and endemic conditions.
RESULTS: The effect of increased density of contacts during Hajj was estimated to generate a 78-fold increase in disease transmission that impacts not only pilgrims but also the local population. Quadrivalent ACWY vaccination was found to be very effective in reducing the risk of outbreak during Hajj. Hajj has more limited impact on IMD transmission and exportation in the pilgrim countries of origin, although not negligible given the size of the population considered.
CONCLUSIONS: The analysis performed highlighted the amplifying effect of mass gathering on N. meningitidis transmission and confirm vaccination as a very effective preventive measure to mitigate outbreak risks.
METHODS: We developed a meta-population model to represent the transmission dynamics of Neisseria meningitidis and the impact of Hajj pilgrimage on the risk of invasive meningococcal disease (IMD) for pilgrims population, local population at the Hajj site and country of origin of Hajj pilgrims. This model was calibrated using data on IMD over 17 years (1995-2011) and further used to simulate potential changes in vaccine policy and endemic conditions.
RESULTS: The effect of increased density of contacts during Hajj was estimated to generate a 78-fold increase in disease transmission that impacts not only pilgrims but also the local population. Quadrivalent ACWY vaccination was found to be very effective in reducing the risk of outbreak during Hajj. Hajj has more limited impact on IMD transmission and exportation in the pilgrim countries of origin, although not negligible given the size of the population considered.
CONCLUSIONS: The analysis performed highlighted the amplifying effect of mass gathering on N. meningitidis transmission and confirm vaccination as a very effective preventive measure to mitigate outbreak risks.
摘要：
背景：大规模集会不仅可以在现场引发重大疫情，而且还可以促进传染性病原体的全球传播。朝圣是全球最大的群众集会活动之一，每年有来自世界各地的200多万朝圣者聚集在一起，造成严重的交通拥堵。
方法：我们开发了一个群体模型来表示脑膜炎奈瑟菌的传播动态以及朝圣对朝圣者人群侵袭性脑膜炎球菌病（IMD）风险的影响，朝圣地点的当地人口和朝圣朝圣者的原籍国。该模型使用17年（1995-2011年）的IMD数据进行校准，并进一步用于模拟疫苗政策和流行条件的潜在变化。
结果：据估计，朝圣期间接触密度增加的影响使疾病传播增加了78倍，不仅影响朝圣者，还影响当地人口。发现四价ACWY疫苗接种在降低朝圣期间爆发的风险方面非常有效。朝圣对来源国的IMD传播和出口的影响有限，尽管考虑到人口规模不可忽视。
结论：所进行的分析强调了大规模聚集对脑膜炎奈瑟氏球菌传播的放大作用，并确认疫苗接种是减轻爆发风险的非常有效的预防措施。
方法：我们开发了一个群体模型来表示脑膜炎奈瑟菌的传播动态以及朝圣对朝圣者人群侵袭性脑膜炎球菌病（IMD）风险的影响，朝圣地点的当地人口和朝圣朝圣者的原籍国。该模型使用17年（1995-2011年）的IMD数据进行校准，并进一步用于模拟疫苗政策和流行条件的潜在变化。
结果：据估计，朝圣期间接触密度增加的影响使疾病传播增加了78倍，不仅影响朝圣者，还影响当地人口。发现四价ACWY疫苗接种在降低朝圣期间爆发的风险方面非常有效。朝圣对来源国的IMD传播和出口的影响有限，尽管考虑到人口规模不可忽视。
结论：所进行的分析强调了大规模聚集对脑膜炎奈瑟氏球菌传播的放大作用，并确认疫苗接种是减轻爆发风险的非常有效的预防措施。
