2000-2022年北京市流行性脑脊髓膜炎病例年龄分布特征及病原学监测分析

Analysis of the age distribution characteristics and pathogen surveillance of meningococcal meningitis cases in Beijing from 2000 to 2022

目的 分析北京市2006年将A群C群流脑多糖疫苗(Group A and C meningococcal polysaccharide vaccine,MPSV-AC)疫苗纳入免疫规划前后北京市流行性脑脊髓膜炎(流脑)流行特征及脑膜炎球菌(Neisseria meningitidis,Nm)血清群变迁变化趋势,评价加强免疫接种程序(第1剂3岁、第2剂9岁)疫苗控制疾病效果,为优化疫苗免疫策略提供科学依据。方法 收集2000-2022年北京市流脑报告病例、2014-2020年国家监测点健康人群Nm带菌率调查数据,分析发病时间趋势、年龄分布特征及Nm血清群变迁情况。结果 将MPSV-AC纳入免疫规划后,发病率由2004年的1.49/10万下降至2007年的0.21/10万,2008-2010年由0.13/10万下降至0.06/10万,2011年以后为0~0.03/10万。MPSV-AC纳入免疫规划前6年高发年龄人群为1、0和15~<20岁年龄组,年均发病率分别为5.08/10万、2.78/10万和1.66/10万。纳入免疫规划后5年全年龄组发病率显著下降,0、1~<6和6~<10岁年龄组较2000-2005年分别下降41.95%、 87.20%和79.98%, 10~<20、≥20岁年龄组下降幅度较1~<10岁人群略低,为76.10%、74.01%, 2011-2022年各年龄组发病率持续维持在低水平,年均发病率较2000-2005年下降幅度在95%以上。病原监测结果阳性40例,以C群、A群、B群和不可分群为主,分别为12例(30.00%)、11例(27.50%)、6例(15.00%)和6例(15.00%),2011年以来无A群报告,W群占比相对上升。2014-2020年健康人群总带菌率为2.29%(328/14 319),各年带菌率为0.68%~3.32%,维持在较低水平;不可分群、B群和W群分别为256例(78.05%)、 53例(16.16%)和9例(2.74%);2014年之后无C群检出,2015年后无A群检出。结论 北京市MPSV-AC疫苗加强免疫接种程序显著降低了<20岁人群全年龄组发病率;优势流行Nm血清群呈现由A群和C群向B群和W群转变趋势,应继续加强流脑监测,必要时考虑是否将MPSV-AC加强剂次调整为含W群成分疫苗。

Objective To describe the epidemiological characteristics of meningococcal meningitis incidence and Neisseria meningitides(Nm)serogroup variation trends in Beijing before and after the inclusion of Group A and C meningococcal polysaccharide vaccine(MPSV-AC)in the immunization program in 2006,and to evaluate the effectiveness of strengthening the immunization schedule in Beijing(the first dose at age 3,the second dose at age 9)in controlling the disease.This study aims to provide a scientific basis for optimizing vaccine immunization strategies.Methods Data on reported meningitis cases in Beijing from 2000 to 2022 and MM carriage rates in healthy populations from national surveillance sites from 2014 to 2020 were collected for analysis of trends in incidence,age distribution characteristics,and the Nm serogroup transition.Results After the inclusion of the MPSV-AC vaccine in the immunization program in 2006,the incidence of MM in Beijing decreased from 1.49/100000 in 2004 to 0.21/100000 in 2007 and decreased from 0.13/100000 to 0.06/100000 in 2008-2010.Since 2011,the incidence rate has fluctuated between 0 and 0.03/100000.Before the inclusion of MPSV-AC vaccine,the high-risk age groups were 0 years,one year,and 15-19 years,with an average annual incidence rate of 2.78/100000,5.08/100000,and 1.66/100000,respectively.After the inclusion of the MPSV-AC,the annual incidence rate significantly decreased in all age groups.The reduction in incidence rates were 41.95%,87.20%,and 79.98%for the 0-year group,1-5-year group,and 6-9-year group,respectively.The reduction in incidence rates for the 10-19-year group and the group aged 20 and above were slightly lower than 1-<10 group at 76.10%and 74.01%,respectively.From 2011 to 2022,the annual incidence rates in all age groups remained low,with a decline magnitude of more than 95%compared to the period from 2000 to 2005.Meningococcal meningitis pathogen surveillance from 2007 to 2019 identified 40 cases of Nm positive,with the predominant serogroups C,A,B,and ungroupable,accounting for 30.00%(12 cases),27.50%(11 cases),15.00%(6 cases),and 15.00%(6 cases),respectively.No case of group A Meningococcal meningitis has been reported since 2011,and there has been a relative increase in cases caused by serogroup W in 2018 and 2019.The overall positive rate of Nm isolation in healthy populations was 2.29%(328/14319)from 2014 to 2020,with annual carriage rates fluctuating between 0.68%and 3.32%,maintaining a relatively low level.Unclassified serogroup,serogroup B,and serogroup W accounted for 78.05%(256/328),16.16%(53/328),and 2.74%(9/328),respectively.No serogroup C was detected after 2014,and no serogroup A was detected after 2015.Conclusions The MPSV-AC vaccine with a booster immunization schedule in Beijing reduced the incidence rate significantly in the population under 20 years old.The predominant circulating serogroups are shifting from A and C to B and W,so we suggest strengthening meningococcal epidemiological and pathogenic monitoring.When necessary,consider adjusting the booster doses of MPSV-AC to vaccines with components targeting serogroup W.