百色市2010年麻疹疫苗强化免疫活动分析

目的 总结分析百色市麻疹疫苗强化免疫活动的数据,为制定"消除麻疹"策略提供依据.方法 对百色市所有8月龄~14岁儿童(包括流动儿童),无论既往有无接种史或患病史,均接种1剂次麻疹疫苗.通过收集整理全市MV强化免疫报表数据和现场评估等情况,采用流行病学方法进行分析.结果 本次强化免疫摸底应种儿童数为699 354人,报告接种人数669 411人,报告接种率为95.72%;麻疹疫苗强化免疫疑似预防接种异常反应报告发生率为2.09/10万;强化免疫后全市尚无麻疹病例报告.结论 麻疹疫苗强化免疫是控制和消除麻疹的有效措施,可迅速提高人群免疫水平,控制麻疹的暴发或流行效果显著.     

Measles supplemental immunization activities improve measles vaccine coverage and equity: Evidence from Kenya, 2002

OBJECTIVES: To compare the measles vaccine coverage achieved through the routine vaccination program with that achieved during the 2002 supplemental immunization activity (SIA) at the national and provincial level, the percentage of previously unvaccinated children (zero-dose children) reached during the SIA, and the equity of measles vaccine coverage among children aged 9-23 months in Kenya. METHODS: Using data from a post-SIA coverage survey conducted in Kenya, we compute routine and SIA measles vaccine coverage and the percent of zero-dose children vaccinated during the SIA at the national and provincial level. Nationwide and for each province, we use the concentration index (CI) to measure equity of measles vaccine coverage. RESULTS: The SIA improved both coverage and equity, achieving significantly higher coverage in all provinces with routine measles vaccination coverage less than 80%, reached a large percentage of zero-dose children in these provinces, and reached more children belonging to the poorest households. CONCLUSION: Overall, by improving both measles vaccine coverage and equity in Kenya, the 2002 SIA reduced the gap in immunity between rich and poor households. Measles SIAs provide an ideal platform for delivering other life-saving child health interventions.     

合肥市适龄儿童麻疹疫苗强化免疫效果评价

目的了解合肥市适龄儿童麻疹疫苗(MV)强化免疫活动(SIA)效果及影响因素,为调整和实施消除麻疹策略提供参考。方法应用分层随机抽样法,选择合肥市社区疫苗接种门诊、幼儿园、小学、中学等作为研究点,分析8月龄～14岁儿童SIA前后麻疹抗体水平。SIA前后分别调查儿童340名和348名,应用描述统计方法,分析SIA前后麻疹流行状况。结果合肥市适龄儿童MV总体接种率为98.04%。SIA后麻疹抗体阳性率、几何平均滴度(GMT)均上升,麻疹抗体阳性率为91.38%。1～4岁组、≥3次免疫史者GMT分别为最高,Logistic多元回归分析显示,1次免疫史者抗体保护水平低。2010年麻疹发病率为0.81/10万,较2009年下降91.86%,发病年龄以婴儿为主,≥2次免疫史者病例构成比最低。结论在麻疹逐渐减弱流行阶段,需要规范适龄儿童首剂次、2剂次MV常规免疫,开展必要强化免疫,加强免疫规划和病例监测质量管理。     

Secondary measles vaccine failures identified by measurement of IgG avidity: high occurrence among teenagers vaccinated at a young age

Failure to seroconvert (primary vaccine failure) is believed to be the principal reason (approx. > 95%) why some vaccinees remain susceptible to measles and is often attributed to the persistence of maternal antibodies in children vaccinated at a young age. Avidity testing is able to separate primary from secondary vaccine failures (waning and/or incomplete immunity), but has not been utilized in measles epidemiology. Low-avidity (LA) and high-avidity (HA) virus-specific IgG antibodies indicate primary and secondary failure, respectively. Measles vaccine failures (n = 142; mean age 10.1 years, range 2-22 years) from an outbreak in 1988-9 in Finland were tested for measles-virus IgG avidity using a protein denaturating EIA. Severity of measles was recorded in 89 failures and 169 non-vaccinees (mean age 16.2 years, range 2-22 years). The patients with HA antibodies (n = 28) tended to have clinically mild measles and rapid IgG response. Among failures vaccinated at < 12, 12-15 and > 15 months of age with single doses of Schwarz-strain vaccine in the 1970s, 50 (95% CI 1-99), 36 (CI 16-56) and 25% (CI 8-42) had HA antibodies, respectively. When a single measles, mumps and rubella (MMR) vaccine had been given after 1982 at 15 months of age, only 7% (CI 0-14) showed HA antibodies. Omitting re-vaccinees and those vaccinated at < 15 months, Schwarz-strain recipients had 3.6 (CI 1.1-11.5) higher occurrence of HA responses compared to MMR recipients. Apart from one municipality, where even re-vaccinees had high risk of primary infection, 89% (CI 69 to approximately 100) of the infected re-vaccinees had an HA response. Secondary measles-vaccine failures are more common than was more previously thought, particularly among individuals vaccinated in early life, long ago, and among re-vaccinees. Waning immunity even among individuals vaccinated after 15 months of age, without the boosting effect of natural infections should be considered a relevant possibility in future planning of vaccination against measles.     

Impact of measles supplementary immunization activities on reaching children missed by routine programs

BackgroundMeasles supplementary immunization activities (SIAs) are vaccination campaigns that supplement routine vaccination programs with a recommended second dose opportunity to children of different ages regardless of their previous history of measles vaccination. They are conducted every 2–4 years and over a few weeks in many low- and middle-income countries. While SIAs have high vaccination coverage, it is unclear whether they reach the children who miss their routine measles vaccine dose. Determining who is reached by SIAs is vital to understanding their effectiveness, as well as measure progress towards measles control.MethodsWe examined SIAs in low- and middle-income countries from 2000 to 2014 using data from the Demographic and Health Surveys. Conditional on a child’s routine measles vaccination status, we examined whether children participated in the most recent measles SIA.ResultsThe average proportion of zero-dose children (no previous routine measles vaccination defined as no vaccination date before the SIA) reached by SIAs across 14 countries was 66%, ranging from 28% in São Tomé and Príncipe to 91% in Nigeria. However, when also including all children with routine measles vaccination data, this proportion decreased to 12% and to 58% when imputing data for children with vaccination reported by the mother and vaccination marks on the vaccination card across countries. Overall, the proportions of zero-dose children reached by SIAs declined with increasing household wealth.ConclusionsSome countries appeared to reach a higher proportion of zero-dose children using SIAs than others, with proportions reached varying according to the definition of measles vaccination (e.g., vaccination dates on the vaccination card, vaccination marks on the vaccination card, and/or self-reported data). This suggests that some countries could improve their targeting of SIAs to children who miss other measles vaccine opportunities. Across all countries, SIAs played an important role in reaching children from poor households.     

Controlling measles using supplemental immunization activities: A mathematical model to inform optimal policy

BackgroundThe Measles & Rubella Initiative, a broad consortium of global health agencies, has provided support to measles-burdened countries, focusing on sustaining high coverage of routine immunization of children and supplementing it with a second dose opportunity for measles vaccine through supplemental immunization activities (SIAs). We estimate optimal scheduling of SIAs in countries with the highest measles burden.MethodsWe develop an age-stratified dynamic compartmental model of measles transmission. We explore the frequency of SIAs in order to achieve measles control in selected countries and two Indian states with high measles burden. Specifically, we compute the maximum allowable time period between two consecutive SIAs to achieve measles control.ResultsOur analysis indicates that a single SIA will not control measles transmission in any of the countries with high measles burden. However, regular SIAs at high coverage levels are a viable strategy to prevent measles outbreaks. The periodicity of SIAs differs between countries and even within a single country, and is determined by population demographics and existing routine immunization coverage.ConclusionsOur analysis can guide country policymakers deciding on the optimal scheduling of SIA campaigns and the best combination of routine and SIA vaccination to control measles.     

Immunogenicity of aerosol measles vaccine given as the primary measles immunization to nine-month-old Mexican children

Aerosol measles vaccination has been found to be more immunogenic than subcutaneous administration as a booster in school aged children, and immunogenic in 12-month-old children as a primary dose. The objective of the study was to evaluate immunogenicity to aerosol measles vaccine in 9-month-old children. METHODS: Nine-months-old infants received Edmonston-Zagreb measles vaccine by aerosol (10(3.58) CCID50/0.1 mL, estimated retained dose 10(2.81) CCID50 or subcutaneous route (10(4.28) CCID50/0.5 mL); cellular and humoral immunity and adverse events were assessed. RESULTS: Measles-specific T cell proliferative responses developed in 42% of children given aerosolized vaccine compared with 67% of those who received subcutaneous vaccine (p = 0.01); the mean stimulation index (SI) was 4.4+/-0.7 versus 6.9+/-1, respectively, (p = 0.05). Seroconversion rates were 33 and 92% after aerosol or subcutaneous immunization (p < 0.001). Among infants who developed serologic responses, measles geometric mean titers (GMT; 95% CI) by neutralizing antibody assay were 215 mIU/mL (115-400) in aerosol vaccine recipients and 411 mIU/mL (345-490) in those given subcutaneous vaccine (p = 0.06). CONCLUSIONS: The proportion of 9-month-old infants who developed cellular and/or humoral immunity to measles was lower in the aerosol group but measles antibody and T cell responses were comparable among those who developed measles immunity. Differences in response rates are attributable to the lower aerosol dose. Improving aerosol delivery or increasing the dose may enhance immunogenicity of primary aerosol measles vaccination in this age group.     

Measles antibody levels among vaccinated and unvaccinated children 6–59 months of age in the Democratic Republic of the Congo, 2013–2014

BackgroundMeasles is endemic in the Democratic Republic of the Congo (DRC), and 89–94% herd immunity is required to halt its transmission. Much of the World Health Organization African Region, including the DRC, has vaccination coverage below the 95% level required to eliminate measles, heightening concern of inadequate measles immunity.MethodsWe assessed 6706 children aged 6–59 months whose mothers were selected for interview in the 2013–2014 DRC Demographic and Health Survey. History of measles was obtained by maternal report, and classification of children who had measles was completed using maternal recall and measles immunoglobulin G serostatus obtained from a multiplex chemiluminescent automated immunoassay dried blood spot analysis. A logistic regression model was used to identify associations of covariates with measles and seroprotection, and vaccine effectiveness (VE) was calculated.ResultsOut of our sample, 64% of children were seroprotected. Measles vaccination was associated with protection against measles (OR: 0.15, 95% CI: 0.03, 0.81) when administered to children 12 months of age or older. Vaccination was predictive of seroprotection at all ages. VE was highest (88%) among children 12–24 months of age.ConclusionOur results demonstrated lower than expected seroprotection against measles among vaccinated children. Understanding the factors that affect host immunity to measles will aid in developing more efficient and effective immunization programs in DRC.     

2008年成都市麻疹减毒活疫苗强化免疫效果评价

目的评估成都市2008年麻疹减毒活疫苗（MV）强化免疫效果。方法综合分析强化免疫期间的现场调查、快速评估报告和麻疹监测系统的病例资料。结果该次强化免疫接种适龄儿童1678854人,报告接种率和评估接种率均在98％以上,2008年报告麻疹疑似病例357例,经实验室检测确诊和临床诊断病例227例,发病率2．24／／10万,较上年下降69．49％。结论成都市2008年麻疹疫苗强化免疫效果显著,麻疹发病显著降低。     

Duration of immunity following immunization with live measles vaccine: 15 years of observation in Zhejiang Province, China

The duration of immunity following measles vaccination of 2882 immunized children has been investigated in a closed region of China for 15 years. A total of 1002 of the children were treated as primary immunization subjects, and 1547 as reimmunization subjects. These two cohorts were not in contact with known wild measles virus over the whole observation period, and the results obtained probably reflected the antibody responses to measles vaccine alone. The remaining 333 vaccinees came into contact with wild measles virus, and this permitted evaluation of the protective effect of the measles vaccines tested: 4 children experienced very mild clinical measles, and 329 experienced subclinical infection, including 12 who had had undetectable haemagglutination-inhibition antibodies for 9-10 years. These results indicate that the immunity induced by successful primary immunization may persist for at least 15 years. Within this period, a second dose of vaccine only induces low antibody responses which decrease rapidly to their original levels. This provides strong evidence that the immunity produced by primary immunization is long-lasting. However, there were some indications that reimmunization might produce better effects if live attenuated measles virus were used with a longer interval between doses.     

Seroprevalence of Antibodies to Measles, Mumps, and Rubella among Thai Population: Evaluation of Measles/MMR Immunization Programme

Stored serum specimens, from four regions of Thailand, of healthy children attending well baby clinics and of healthy people with acute illnesses visiting outpatient clinics were randomly sampled and tested for IgG antibody to measles, mumps, and rubella (MMR). The immunity patterns of rubella and mumps fitted well with the history of rubella and MMR vaccination, seroprotective rates being over 85% among those aged over seven years. A high proportion of younger children acquired the infection before the age of vaccination. MMR vaccination should preferably be given to children at an earlier age. For measles, 73% seroprotective rates among children, aged 8-14 years, who should have received two doses of measles/MMR vaccine, were lower than expected. This finding was consistent with the age-group reported in outbreaks of measles in Thailand. The apparent ineffectiveness (in relation to measles) of MMR immunization of 1^st grade students warrants further studies.Key words: Antibodies, Immunization, Measles, Measles vaccine, Mumps, MMR vaccine, Rubella, Seroepidemiologic studies, Seroprevalence, Vaccination, Thailand     

Added value of the measles-rubella supplementary immunization activity in reaching unvaccinated and under-vaccinated children,a cross-sectional study in five Indian districts, 2018–20

IntroductionSupplementary immunization activities (SIAs) aim to interrupt measles transmission by reaching susceptible children, including children who have not received the recommended two routine doses of MCV before the SIA. However, both strategies may miss the same children if vaccine doses are highly correlated. How well SIAs reach children missed by routine immunization is a key metric in assessing the added value of SIAs.MethodsChildren aged 9 months to younger than 5 years were enrolled in cross-sectional household serosurveys conducted in five districts in India following the 2017–2019 measles-rubella (MR) SIA. History of measles containing vaccine (MCV) through routine services or SIA was obtained from documents and verbal recall. Receipt of a first or second MCV dose during the SIA was categorized as “added value” of the SIA in reaching un- and under-vaccinated children.ResultsA total of 1,675 children were enrolled in these post-SIA surveys. The percentage of children receiving a 1st or 2nd dose through the SIA ranged from 12.8% in Thiruvananthapuram District to 48.6% in Dibrugarh District. Although the number of zero-dose children prior to the SIA was small in most sites, the proportion reached by the SIA ranged from 45.8% in Thiruvananthapuram District to 94.9% in Dibrugarh District. Fewer than 7% of children remained measles zero-dose after the MR SIA (range: 1.1–6.4%) compared to up to 28% before the SIA (range: 7.3–28.1%).DiscussionWe demonstrated the MR SIA provided considerable added value in terms of measles vaccination coverage, although there was variability across districts due to differences in routine and SIA coverage, and which children were reached by the SIA. Metrics evaluating the added value of an SIA can help to inform the design of vaccination strategies to better reach zero-dose or undervaccinated children.     

Measles seroprevalence of an adolescent population vaccinated with a single dose of measles vaccine before their first birthday

This study determined the age-specific measles seroprevalence of an adolescent population in Ankara vaccinated with a single dose of measles vaccine before their first birthday. The study sample included 440 adolescents (227 female, 213 male) aged 9-16 years admitted to the Adolescent Outpatient Clinic of Hacettepe University Faculty of Medicine. For each participant, a questionnaire was completed and measles specific IgG antibodies screened quantitatively by the enzyme linked immunosorbent assay. Of the 440 subjects screened for measles antibodies, 114 (25.9 %) were seronegative. Measles seronegativity according to sex and age groups were, 32.6, 24.7, 13.3% in females and 29.5, 30.1, 6.3% in males in the age groups of 9-11, 12-14, 15-16 years, respectively. In countries where the two dose vaccination schedule against measles has not been incorporated to the national immunization program, the adolescent health maintenance visit at age 11-12 years should serve as an opportunity to evaluate vaccination status and administer MMR vaccine to all adolescents who have not received two doses at the recommended ages.     

Progress in measles control--Zambia, 1999-2004

Zambia, a southern African country with estimated population of 11.6 million in 2005, reported 1,698-23,518 measles cases annually during 1991-1999. During that period, measles was considered one of the five major causes of morbidity and mortality among children aged <5 years. During 1999-2004, the challenge of controlling measles led Zambia to try several strategies in succession. In addition to a single dose of measles vaccine offered at age 9 months through routine services, in 1999, measles supplemental immunization activities (SIAs) targeting children aged 9 months-4 years were held in four urban centers. Those activities were followed in 2000 by a subnational measles SIA targeting children aged 9 months-4 years in approximately half of the country's 72 districts. In 2003, Zambia adopted a strategy of accelerated measles control that included strengthening routine vaccination, providing a second opportunity for measles immunization for all children, and conducting case-based surveillance. As part of this strategy, a nationwide measles SIA targeting all children aged 6 months-14 years was conducted in 2003. This report summarizes progress in measles control in Zambia during 1999--2004, as measured through surveillance data, which demonstrates a marked reduction in measles transmission after the 2003 SIA.     

Cost analysis of supplemental immunization activities to deliver measles immunization to children in Anambra state,south-east Nigeria

BackgroundMeasles immunization is critical for reducing the societal burden of the disease, especially among children. However, the costs of the measles supplemental immunization activities, which are the main vaccine deployment strategy, are usually high and financing such immunization activities is a serious challenge in Nigeria. In Nigeria, little or no information exists on the costs of measles supplemental immunization activity for planning and sustenance of immunization programmes. This study aimed to determine the cost per child immunized and cost structure of a follow-up supplemental immunization activity (SIA) for measles immunization to children.MethodData on costs and outputs of SIA were collected from six Local Government area (LGAs) immunization offices in Anambra state, southeast Nigeria. The ingredient approach was used for costing, based on the providers’ perspective. The sample results were extrapolated to state estimates using volume weighted mean method. The major indicator considered was cost per child immunized. Two-way sensitivity analysis was used to test the robustness of the results.ResultThe cost per child immunized through SIA was $1.37 and the cost per child for operational cost only was $0.81. The total cost of the SIA for the sample was $345,069.35 and the operational cost was $204,969.46. The cost of personnel (43.99%) and vaccine (36.22%) contributed the highest percentage to the total cost of SIA. The cost of personnel and transportation took the first (74.6%) and second (7.10%) highest percentages of the operational cost for the sample. The estimated total and operational costs of measles SIA for the state were $1,279,127.84 and $759,795.52 respectively.ConclusionThe cost per child immunized with measles containing vaccine through SIA is relatively high in Nigeria. There is a need to review the activities with SIA, so as to ensure that resources are efficiently allocated and used for different activities of the programme.     

Assessing the cost-effectiveness of different measles vaccination strategies for children in the Democratic Republic of Congo

IntroductionOne of the goals of the Global Measles and Rubella Strategic Plan is the reduction in global measles mortality, with high measles vaccination coverage as one of its core components. While measles mortality has been reduced more than 79%, the disease remains a major cause of childhood vaccine preventable disease burden globally. Measles immunization requires a two-dose schedule and only countries with strong, stable immunization programs can rely on routine services to deliver the second dose. In the Democratic Republic of Congo (DRC), weak health infrastructure and lack of provision of the second dose of measles vaccine necessitates the use of supplementary immunization activities (SIAs) to administer the second dose.MethodsWe modeled three vaccination strategies using an age-structured SIR (Susceptible-Infectious-Recovered) model to simulate natural measles dynamics along with the effect of immunization. We compared the cost-effectiveness of two different strategies for the second dose of Measles Containing Vaccine (MCV) to one dose of MCV through routine immunization services over a 15-year time period for a hypothetical birth cohort of 3 million children.ResultsCompared to strategy 1 (MCV1 only), strategy 2 (MCV2 by SIA) would prevent a total of 5,808,750 measles cases, 156,836 measles-related deaths and save U.S. $199 million. Compared to strategy 1, strategy 3 (MCV2 by RI) would prevent a total of 13,232,250 measles cases, 166,475 measles-related deaths and save U.S. $408 million.DiscussionVaccination recommendations should be tailored to each country, offering a framework where countries can adapt to local epidemiological and economical circumstances in the context of other health priorities. Our results reflect the synergistic effect of two doses of MCV and demonstrate that the most cost-effective approach to measles vaccination in DRC is to incorporate the second dose of MCV in the RI schedule provided that high enough coverage can be achieved.     

2009年广东省8月龄至14岁儿童麻疹疫苗强化免疫活动分析

目的分析总结2009年3—4月广东省麻疹疫苗（MV）强化免疫活动的有关数据,为制定达到消除麻疹目标策略提供依据。方法该次强化免疫对象为广东省内8月龄至14周岁儿童（包括流动儿童）,无论既往有无接种史或患病史,1个月内均接种1剂次麻疹疫苗。通过收集整理广东省MV强化免疫报表数据和现场评估等情况,采用流行病学方法进行分析。结果全省摸底登记8月龄至14周岁儿童共20 437 255人,报告接种数为19 952 519人,报告接种率为97.63%,强化免疫活动前麻疹疫苗调查接种率为71.66%,与强化免疫活动后调查接种率（98.10%）比较,差异有统计学意义（P〈0.01）。活动前儿童家长知晓率为91.86%,活动后期知晓率为98.48%,差异有统计学意义（P〈0.01）;麻疹疫苗强化免疫疑似预防接种异常反应报告发生率为4.21/10万;麻疹疫苗强化免疫后,2009年5—12月麻疹发病数较去年同期下降92.59%,麻疹发病率从2008年的16.10/10万下降到2009年的2.22/10万。结论麻疹疫苗强化免疫是控制和消除麻疹的有效措施,政府主导、多部门配合、声势浩大的宣传发动和良好的组织实施是强化免疫成功的关键。     

Immunogenicity of second dose measles-mumps-rubella (MMR) vaccine and implications for serosurveillance.

Measles and mumps, but not rubella, outbreaks have been reported amongst populations highly vaccinated with a single dose of measles-mumps-rubella (MMR) vaccine. Repeated experience has shown that a two-dose regime of measles vaccine is required to eliminate measles. This paper reports the effect of the first and second MMR doses on specific antibody levels in a variety of populations.2-4 years after receiving a first dose of MMR vaccine at age 12-18 months, it was found that a large proportion of pre-school children had measles (19.5%) and mumps (23.4%) IgG antibody below the putative level of protection. Only a small proportion (4.6%) had rubella antibody below the putative protective level. A total of 41% had negative or equivocal levels to one or more antigens. The proportion measles antibody negative (but not rubella or mumps) was significantly higher in children vaccinated at 12 months of age than at 13-17 months. There was no evidence for correlation of seropositivity to each antigen, other than that produced by a small excess of children (1%) negative to all three antigens. After a second dose of MMR, the proportion negative to one or more antigens dropped to <4%. Examination of national serosurveillance data, found that following an MR vaccine campaign in cohorts that previously received MMR, both measles and rubella antibody levels were initially boosted but declined to pre-vaccination levels within 3 years.Our study supports the policy of administering a second dose of MMR vaccine to all children. However, continued monitoring of long-term population protection will be required and this study suggests that in highly vaccinated populations, total measles (and rubella) IgG antibody levels may not be an accurate reflection of protection. Further studies including qualitative measures, such as avidity, in different populations are merited and may contribute to the understanding of MMR population protection.     

Measles in Papua New Guinea: An age-specific serological survey

We aimed to determine the proportion of the population in Madang (Papua New Guinea) immune to measles infection by age groups, with respect to immunization status and study location, using dried blood sampling technology. We performed a prospective cross-sectional sero-survey. Population immunity against measles was sub-optimal (77%) and reported measles vaccine coverage in children <10 years of age was low (41%). The urban population was more susceptible to measles infection, compared with the rural population (66% vs 79% immune, aOR = 0.6, p = 0.05). Sero-conversion and long term protection rates appeared to be higher when at least one dose of vaccine was provided at or after 12 months of age (84% vs 59%, aOR = 4.3, p = 0.004). Such a dose is, however, not currently prescribed by the national immunization schedule.     

德州市1999～2002年麻疹控制与监测分析

为了解德州市麻疹流行病学特点和麻疹监测系统运行状况 ,对 1999～ 2 0 0 2年麻疹监测的数据进行了分析。结果显示 :4年共报告麻疹疑似病例 2 6 4例 ,比常规传染病报告系统多出 138% ,确诊麻疹 12 3例 ,及时报告、及时调查和血清标本采集率分别达到 10 0 %、10 0 %、99%。麻疹发病呈散发和爆发并存的流行病学模式 ,爆发病例占总发病数的 5 1%。麻疹散发以学龄前儿童和成年人为主 ,爆发病例以学龄儿童为主。确诊病例中有麻疹疫苗 (MV)免疫史者占 32 5 2 % ,无免疫史者占 19 5 1% ,免疫史不详者占 4 7 97%。 3年麻疹监测报告的及时性、完整性和病例调查的完整性均达到 10 0 %。发病主要原因是MV接种率低和免疫失败。应在提高常规免疫接种率和接种质量的同时 ,要抓好大年龄儿童的MV强化免疫 ,进一步提高人群的免疫水平 ,预防控制麻疹爆发。