Simões Maria João, Bettencourt Célia, De Paola Rosita, Giuliani Maria, Pizza Mariagrazia, Moschioni Monica, Machado Jorge
Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Lisboa, Portugal.
GSK Vaccines, Siena, Italy.
PLoS One. 2017 May 1;12(5):e0176177. doi: 10.1371/journal.pone.0176177. eCollection 2017.
Although the incidence of meningococcal disease has been declining over the past decade in Portugal MenB meningococci is still an important cause of meningitis and sepsis. The aim of this study was to estimate the strain coverage of the 4CMenB vaccine in Portugal in order to support health policies for prevention and control of meningococcal disease.
Since 2002 the clinical and laboratory notification of meningococcal disease is mandatory in Portugal. National database includes since then all confirmed cases notified to the reference laboratory or to the Directorate of Health. Strains included in this study were all the invasive MenB isolated from the 1st July 2011 to the 30th June 2015, sent to the reference laboratory. To predict the vaccine strain coverage of the 4CMenB the expression and cross-reactivity of the surface antigens fHbp, NadA, NHBA were assessed by the Meningococcal Antigen Typing System (MATS) whereas PorA typing was performed by sequencing. The presence of at least one antigen with a Relative Potency (RP) greater than its MATS-positive bactericidal threshold RP value or the presence of PorA VR2 = 4 was considered to be predictive for a strain to be covered by the 4CMenB vaccine.
The estimated 4CMenB strain coverage in Portugal was 67.9%. The percentage of strain coverage in each of the four epidemiological years ranged from 63.9% to 73.7%. Strains covered by one antigen represent 32.1% of the total of isolates, 29.2% of strains were covered by two antigens and 6.6% by three antigens. No strain had all the four antigens. Antigens that most contributed for coverage were NHBA and fHbp. Data from Portugal is in accordance with the MATS predicted strain coverage in five European countries (England and Wales, France, Germany, Italy and Norway) that pointed to 78% coverage for strains collected in the epidemiological year 2007-2008.
尽管在过去十年中葡萄牙的脑膜炎球菌病发病率一直在下降，但B群脑膜炎球菌仍是脑膜炎和败血症的重要病因。本研究的目的是评估4CMenB疫苗在葡萄牙的菌株覆盖率，以支持脑膜炎球菌病预防和控制的卫生政策。
自2002年以来，葡萄牙强制要求对脑膜炎球菌病进行临床和实验室通报。自那时起，国家数据库包括所有向参考实验室或卫生局通报的确诊病例。本研究纳入的菌株为2011年7月1日至2015年6月30日期间从侵袭性B群脑膜炎球菌分离出的、送至参考实验室的菌株。为预测4CMenB疫苗的菌株覆盖率，通过脑膜炎球菌抗原分型系统（MATS）评估表面抗原fHbp、NadA、NHBA的表达和交叉反应性，而PorA分型则通过测序进行。至少有一种抗原的相对效力（RP）大于其MATS阳性杀菌阈值RP值，或存在PorA VR2 = 4，被认为可预测该菌株能被4CMenB疫苗覆盖。
葡萄牙4CMenB菌株的估计覆盖率为67.9%。四个流行病学年份中各年份的菌株覆盖率在63.9%至73.7%之间。由一种抗原覆盖的菌株占分离株总数的32.1%，由两种抗原覆盖的菌株占29.2%，由三种抗原覆盖的菌株占6.6%。没有菌株具有全部四种抗原。对覆盖率贡献最大的抗原是NHBA和fHbp。葡萄牙的数据与五个欧洲国家（英格兰和威尔士、法国、德国、意大利和挪威）MATS预测的菌株覆盖率一致，这些国家指出2007 - 2008年流行病学年份收集的菌株覆盖率为78%。
