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Abstract：
BackgroundMeningococcus (Neisseria meningitidis) is the causative bacteria of invasive meningococcal disease (IMD), a major cause of meningitis and sepsis. In 2015-16, an outbreak caused by serogroup C meningococci (MenC), belonging to the hyperinvasive strain ST-11(cc-11), resulted in 62 IMD cases in the region of Tuscany, Italy.AimWe aimed to estimate the key outbreak parameters and assess the impact of interventions used in the outbreak response.MethodsWe developed a susceptible-carrier-susceptible individual-based model of MenC transmission, accounting for transmission in households, schools, discos/clubs and the general community, which was informed by detailed data on the 2015-16 outbreak (derived from epidemiological investigations) and on the implemented control measures.ResultsThe outbreak reproduction number (Re) was 1.35 (95% prediction interval: 1.13-1.47) and the IMD probability was 4.6 for every 1,000 new MenC carriage episodes (95% confidence interval: 1.8-12.2). The interventions, i.e. chemoprophylaxis and vaccination of close contacts of IMD cases as well as age-targeted vaccination, were effective in reducing Re and ending the outbreak. Case-based interventions (including ring vaccination) alone would have been insufficient to achieve outbreak control. The definition of age groups to prioritise vaccination had a critical impact on the effectiveness and efficiency of control measures.ConclusionsOur findings suggest that there are no effective alternatives to widespread reactive vaccination during outbreaks of highly transmissible MenC strains. Age-targeted campaigns can increase the effectiveness of vaccination campaigns. These results can be instrumental to define effective guidelines for the control of future meningococcal outbreaks caused by hypervirulent strains.
摘要：
背景脑膜炎球菌是侵袭性脑膜炎球菌病(IMD)的致病菌,脑膜炎和败血症的主要原因.2015-16年，由血清群C脑膜炎球菌（MenC）引起的疫情，属于高侵袭菌株ST-11（cc-11），导致托斯卡纳地区62例IMD病例，意大利。AimWe旨在估计关键的疫情参数，并评估疫情应对中使用的干预措施的影响。方法我们开发了一种基于MenC传播的易感携带者易感个体模型，核算家庭中的传播，学校,迪斯科舞厅/俱乐部和一般社区，2015-16年疫情(来自流行病学调查)和实施的控制措施的详细数据为这一数据提供了依据.结果每1,000例新的MenC携带发作，爆发繁殖次数（Re）为1.35（95％预测间隔：1.13-1.47），IMD概率为4.6（95％置信区间：1.8-12.2）。干预措施，即对IMD病例的密切接触者进行化学预防和疫苗接种以及针对年龄的疫苗接种，有效地减少了Re并结束了疫情。仅基于病例的干预措施（包括环形疫苗接种）不足以实现疫情控制。优先考虑接种疫苗的年龄组的定义对控制措施的有效性和效率具有关键影响。结论我们的研究结果表明，在高传染性MenC菌株爆发期间，没有有效的替代方案可以替代广泛的反应性疫苗接种。以年龄为目标的运动可以提高疫苗接种运动的有效性。这些结果有助于确定有效的指南，以控制由高毒力菌株引起的未来脑膜炎球菌暴发。
