Braeye Toon, Linina Indra, De Roy Rikka, Hutse Veronik, Wauters Magali, Cox Pia, Mak Ruud
Epidemiology of Infectious Diseases, Operational Directorate Public Health and Surveillance, Scientific Institute of Public Health, Julliette Wytsmanstraat 14, 1050 Brussels, Belgium.
Epidemiology of Infectious Diseases, Operational Directorate Public Health and Surveillance, Scientific Institute of Public Health, Julliette Wytsmanstraat 14, 1050 Brussels, Belgium; European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control, Stockholm, Sweden.
Vaccine. 2014 Jul 31;32(35):4393-4398. doi: 10.1016/j.vaccine.2014.06.069. Epub 2014 Jun 25.
In 2012, an increase in mumps notifications occurred in Belgium, affecting young vaccinated adults. At the end of 2012, a mumps outbreak occurred at the Catholic University of Leuven KU Leuven in Flanders. We investigated the outbreak to estimate incidence, mumps vaccine effectiveness and to detect potential risk factors for the disease.
In June 2012, we set up mandatory notification in Flanders and we collected information on circulating genotypes from the National Reference Centre. We conducted a cohort study among KU Leuven students. We defined a case as self-reported parotitis, between September 2012 and March 2013. We distributed web-based questionnaires to a random sample of students. We calculated vaccine effectiveness by comparing the risks in students vaccinated twice with those vaccinated once. We estimated risk ratios (RR) to identify risk factors.
From 16th June 2012 to 1st April 2013, 4061 mumps cases were notified to the regional public health office (30% were vaccinated once and 69% were vaccinated twice). All 16 samples collected at the KU Leuven were genotype G5. Of 717 participants of the cohort study, 38 (5%; 95%CI 4-8%) met the case-definition. All reported being vaccinated with at least one dose of mumps-containing vaccine. The incidence of mumps was 5% among those vaccinated twice and 16% among those vaccinated once (vaccine effectiveness of two doses compared to one: 68%, 95%CI -24% to 92%). The risk of mumps was lower among those vaccinated with two doses of mumps-containing vaccine ≤10 years before (RR: 0.33, 95%CI 0.10-1.02) and higher among students working in a bar (RR: 3.6, 95%CI 1.8-7.0).
Incomplete protection by two doses of mumps-containing vaccine, possible waning immunity and intense social contacts may have contributed to the occurrence of this outbreak in Flanders. Efforts to maintain high vaccination coverage with two doses remain essential. However, the reasons for low vaccine effectiveness must be further explored and additional immunological research for more immunogenic mumps vaccines is necessary.
2012年，比利时腮腺炎报告病例数增加，受影响的是已接种疫苗的年轻成年人。2012年底，法兰德斯的鲁汶天主教大学（KU鲁汶）爆发了腮腺炎疫情。我们对此次疫情进行了调查，以估计发病率、腮腺炎疫苗效力，并检测该疾病的潜在风险因素。
2012年6月，我们在法兰德斯建立了强制报告制度，并从国家参考中心收集了有关流行基因型的信息。我们在KU鲁汶的学生中开展了一项队列研究。我们将2012年9月至2013年3月期间自我报告患腮腺炎的病例定义为病例。我们向随机抽取的学生样本发放了基于网络的问卷。通过比较接种两剂疫苗的学生与接种一剂疫苗的学生的风险来计算疫苗效力。我们估计风险比（RR）以识别风险因素。
从2012年6月16日至2013年4月1日，共有4061例腮腺炎病例报告给了地区公共卫生办公室（30%接种过一剂疫苗，69%接种过两剂疫苗）。在KU鲁汶采集的所有16个样本均为G5基因型。在队列研究的717名参与者中，38例（5%；95%CI 4 - 8%）符合病例定义。所有病例均报告至少接种过一剂含腮腺炎疫苗。接种两剂疫苗者的腮腺炎发病率为5%，接种一剂疫苗者为16%（两剂疫苗相对于一剂疫苗的效力为68%，95%CI -24%至92%）。在接种含腮腺炎疫苗两剂≤10年者中，患腮腺炎的风险较低（RR：0.33，95%CI 0.10 - 1.02），而在酒吧工作的学生中风险较高（RR：3.6，95%CI 1.8 - 7.0）。
两剂含腮腺炎疫苗提供的保护不完整、可能的免疫力减弱以及密切的社会接触可能导致了法兰德斯此次疫情的发生。维持两剂疫苗的高接种覆盖率仍然至关重要。然而，必须进一步探究疫苗效力低下的原因，并且有必要开展更多关于更具免疫原性的腮腺炎疫苗的免疫学研究。
