Measles epidemic in Romania, 1996-1998: assessment of vaccine effectiveness by case-control and cohort studies

A measles epidemic occurred in Romania with 32,915 cases and 21 deaths reported between November 1996 and June 1998, despite high vaccination coverage since the early 1980s. Most cases were unvaccinated children aged <2 years and vaccinated school-aged children. A case-control study among preschool children and a cohort study among primary-school children were conducted to estimate effectiveness of Romanian-produced measles vaccine, and to evaluate age at vaccination and waning immunity as risk factors for vaccine failure. Both studies indicated that measles vaccine was highly effective. One dose reduced the risk for measles by 89% (95% confidence interval (CI) 85, 91); two doses reduced the risk by 96% (95% CI 92, 98). Children vaccinated at <1 year of age were not at increased risk for measles compared with children vaccinated at > or =1 year. Waning immunity was not identified as a risk factor since vaccine effectiveness was similar for children vaccinated 6-8, 9-11, and 12-14 years in the past. Because specific groups were not at risk for vaccine failure, an immunization campaign that targets all school-aged children who lack two doses may be an effective strategy for preventing outbreaks. A mass campaign followed by increased first-dose coverage should provide the population immunity required to interrupt indigenous measles virus transmission in Romania.     

Mass measles vaccination in urban Burkina Faso, 1998

OBJECTIVE: To assess the impact of the National Immunization Days (NIDs) on measles vaccine coverage in Burkina Faso in 1998. METHODS: During the week after the campaign, in which measles vaccine was offered to children aged 9-59 months in six cities regardless of vaccination history, a cluster survey was conducted in Ouagadougou and Bobo Dioulasso, the country's two largest cities. Interviewers visited the parents of 1267 children aged up to 59 months and examined vaccination cards. We analysed the data using cluster sample methodology for the 1041 children who were aged 9-59 months. FINDINGS: A total of 604 (57%) children had received routine measles vaccination prior to the campaign, and 823 (79%) were vaccinated during the NIDs. Among those who had previously had a routine vaccination, 484 (81%) were revaccinated during the NIDs. Among those not previously vaccinated, 339 (78%) received one dose during the NIDs. After the campaign, 943 (91%) children had received at least one dose of measles vaccine. Better socioeconomic status was associated with a higher chance of having been vaccinated routinely, but it was not associated with NID coverage. CONCLUSION: The mass campaign enabled a substantial increase in measles vaccine coverage to be made because it reached a high proportion of children who were difficult to reach through routine methods.     

Measles in Poland in 2003

In Poland 48 measles cases were registered in 2003 (0.13 per 100,000 population)--of which 65% were cases imported from Chechnya and Afghanistan. Measles outbreaks occurred in 3 centers for immigrants. In total, 31 cases were reported, of which 96.8% were unvaccinated, and 93.5% were under 15 years of age. Of 17 local cases, 5 (29.4%) cases occurred in unvaccinated persons, 3 (17.6%) in persons vaccinated with one dose and 7 (41.2%) in those vaccinated with two doses of measles vaccine (administered at the age of 13-15 months and 7 years). Among 12 vaccinated cases only one 2-year old child was recently vaccinated. The remaining cases were in the 3-7 and 10-24 age ranges. The most affected were infants (incidence 0.57 per 100,000), 1-year old (0.28) and 2-year old children (incidence 0.27). Cases among adolescents and adults over 15 years of age increased from 23.5% in 2002 to 47.1% in 2003. The increasing age of locally-acquired cases, together with constantly high immunization coverage indicates high effectiveness of vaccinations in Poland. Out of all reported cases 13 (38%) were hospitalized. There were no deaths due to measles in Poland in 2003. Poland participates in the WHO Measles Elimination Strategy. Presently, the most important is the maintenance of a sensitive and timely surveillance of measles and measles-compatible cases, with serologic confirmation of one rash-like illness per 100 000 population. The performance of the surveillance system is insufficient with only 55 measles-compatible cases reported in 2003 (15% of expected reports). Serologic confirmation of cases was also insufficient, with 22 cases (40.0%) confirmed by IgM ELISA test. These results indicate the need to maintain the high immunisation coverage and improve measles surveillance system.     

Measles outbreak in a northern Pakistani village: epidemiology and vaccine effectiveness

In the spring of 1990, local community health workers reported a measles outbreak in several partially vaccinated villages in the Punial Valley in northern Pakistan. The authors conducted an investigation in one of these villages to assess vaccine coverage and vaccine efficacy and to describe the patterns of measles outbreaks that prevailed in this community. The results of a survey of the entire village revealed two major gaps in vaccine coverage: the small minority Sunni community and children over 3 years of age. Vaccine efficacy was estimated to range from 73 to 90% but was markedly reduced in children who were vaccinated under 12 months of age. The occurrence of an outbreak in a community in which a relatively new vaccination program is primarily directed at younger children has been predicted by theoretical models of measles dynamics and is consistent with the experience of other vaccination programs in the developing world. These observations suggest that, in some areas of the developing world, the age groups targeted to receive measles vaccinations may need to be broadened to ensure adequate coverage to prevent recurrent outbreaks.     

Vaccination of children in Japan

The coverage rates of six vaccines (BCG, polio, DPT, measles, mumps and varicella) and the prevalence of these diseases in Japan were investigated. It was found that 82.2% of children had been inoculated with BCG before their first birthday, and 85.4% were given two doses of polio vaccine before their second birthday. The high acceptance rates of these vaccines seem to be attributable to mass inoculations at health centers. On the other hand, the median age when the first dose of DPT vaccine was given was as late as 22 months. Mass administration of this vaccine during infancy should be performed since about one-quarter of the patients with diphtheria, pertussis or tetanus were less than one year old. The cumulative percentage for measles inoculation failed to reach 60% by the second birthday. Considering that the incidence of measles has not yet been satisfactory lowered and that infants under 23 months of age account for about one-half of this incidence, more children less than 18 months old should be immunized. The ineffective rate of varicella vaccine was found to be 18.2%, although reestimation of its effectiveness may be necessary.     

Measles in Vietnamese refugee children in Hong Kong.

From September 1991-January 1992, there was a measles epidemic in an established refugee camp for 7000 Vietnamese 'Boat People' living in Hong Kong. This 16 week outbreak occurred against a backdrop of poor uptake of measles vaccination and overcrowded living conditions. Two hundred and sixty-two children were affected (155 boys, 107 girls); 235 children (89.7 %) were < 2 years old, age range 5-39 months. Children age 6-11 months had the highest crude attack rate (AR) of 54.3%. The highest age specific crude AR was 83.8% in children aged 14 months. Measles complications affected 234 (89.3%) children. Sixty-six children (25.2%) were admitted to hospital. There were two deaths from pneumonia, giving a case fatality rate of 0.76%. Measles control in refugee camps continues to be a public health challenge.     

Evaluation of a measles-smallpox vaccination campaign by a sero-epidemiologic method.

An assessment technique has been devised whereby children from 30 randomly chosen sampling sites are visited within three days of measles-smallpox vaccination and one month later. Vaccination coverage is measured at house visits and immunologic status is determined by collection of early and late blood samples on filter papers from substratified children in priority age-groups, and by looking at vaccination scars. The methodology was employed in a rural area of the Ivory Coast during the maintenance phase of a measles-smallpox vaccination program; 1762 children from 0--72 months old were inspected. Children in the target age groups, 6--24 months, had a vaccination coverage of 53.6% whereas children outside of the target group had a 10.5% coverage. Of 571 target age children, 94.6% had a measles hemagglutination-inhibition antibody titer of less than 1:10 dilution at the first visit, and were presumed susceptible to measles or vaccine. Of 247 substratified children 6--8 months, 98.3% were susceptible to measles before vaccination; 84.3% of 127 vaccinated children in this age-group sero-converted when re-tested. Of 324 children 9--24 months, 91.7% were susceptible before the campaign; 94.7% of 170 vaccinated children in this age-group converted. A positive history of prior measles or prior measles-vaccination was not a good indicator of measles serologic status. The smallpox vaccination major reaction rate was 93.2%; 91.4% of children with a recent vaccination scar sero-converted to measles vaccine. Thus, the smallpox scar read at the second visit proved the best clinical marker for determining both coverage and immunologic effectiveness of the campaign.     

School-based measles outbreaks: correlation of age at immunization with risk of disease.

During the Spring of 1978, students with a history of previous measles vaccination accounted for over three-forths of 203 cases of measles in a metropolitan county. Seventy cases occurred in two schools where 99% of the students were vaccinated. We analyzed countywide data to determine past patterns of measles vaccination, including outbreak control and vaccination update clinics. We also examined records of children from the two schools to assess the relationship between disease incidence and age at vaccination. When susceptibility was determined by trained health workers rather than by parents, fewer doses of measles vaccine were estimated to be needed. The majority of cases occurred among children 5 to 9 years old. Attack rates were higher for children vaccinated at 12 months of age or younger than for those vaccinated at 13 months of age or older. There were no significant differences in attack rates among children vaccinated at 13 months of age or older. These findings support recommendations for delaying routine measles vaccination until after 12 months of age and suggest that, during outbreaks, all children vaccinated prior to 13 months of age be revaccinated.     

Measles in Poland in 2001

The number of notified measles cases in Poland in 2001 was 133, incidence per 100,000 inhabitants was 0.3. The low incidence has been observed for the last 3 years. Only 73 out of 133 cases were serologically confirmed, 6 other cases were epidemiologically linked to the laboratory confirmed cases. Unvaccinated cases have accounted for almost half of cases. Differences in incidence were noticed across the country and ranged from 0 cases in Opolskie and Zachodniopomorskie voivodeships to 0.7/100,000 in Ma?opolskie and 1.0/100,000 in Swietokrzyskie voivodeship. The highest incidence was observed in the children one year of age (3.7/100,000) and seven years old (2.3/100,000), however, in general, the age distribution of cases has been shifted toward older ages with 44 cases (33% of all cases) in adults. A proportion of children 13-24 months of age vaccinated with first dose of measles vaccine was 77.1%, and proportion of seven years old children vaccinated with second dose of measles vaccine was 81.7%.     

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.     

Pediatric measles cases by residence status in Tel Aviv,Israel

BackgroundMeasles is a vaccine-preventable infectious disease whose outbreaks generally originate from exposure to populations with low vaccination coverage.MethodsThis study compared the rates and morbidity of measles cases in the district of Tel-Aviv during two outbreaks (2012 and 2018–2019) by citizenship and geographic location.ResultsThere were 67 pediatric cases reported in 2012 and 222 in 2018–2019. Cases were more likely to have pneumonia in 2012 as compared to in 2018–2019 (58.2% versus 6.3%) and less likely to report a single vaccination dose (9.5% versus 22.8%, respectively). In 2012, the majority of cases were among children without legal residence (CWLR), while in 2018–2019, they were the minority of cases (N = 54, 80.6% versus N = 51, 23.0%, respectively). In both outbreaks, CWLR were more likely to be less than one year old (the recommended age for the first dose of measles vaccination), unvaccinated or with unknown vaccine status, to be treated in a tertiary care center, and to have pneumonia than children with Israeli citizenship (CC). In both outbreaks, CWLR lived in a concentrated neighborhood in Southern Tel Aviv.ConclusionWhile the two measles outbreaks differed in overall morbidity, in both outbreaks CWLR presented with a more severe clinical presentation and were less likely to be vaccinated (in part due to their younger age) than CC. The geographically concentration of CWLR was distinct from that of the CC in both outbreaks. Healthcare professionals should promote vaccination uptake and increase parents' awareness to early signs of the disease.     

Assessing measles vaccine failure in Tianjin,China

Despite increasing global measles vaccination coverage, progress toward measles elimination has slowed in recent years. In China, children receive a measles-containing vaccine (MCV) at 8 months, 18–24 months, and some urban areas offer a third dose at age 4–6 years. However, substantial measles cases in Tianjin, China, occur among individuals who have received multiple MCV doses. This study describes the vaccination history of measles cases 8 months – 19 years old. Data came from measles cases in Tianjin’s reportable disease surveillance system (2009–2013), and from a case control study (2011–2015). Twenty-nine percent of those in the surveillance dataset and 54.4% of those in the case series received at least one dose of MCV. The minimum and median time-to-diagnosis since vaccination revealed an increase in time since vaccination for incremental doses. Considerable measles cases in Tianjin occur in vaccinated children, and further research is needed to understand the reasons for vaccine failure.     

麻疹疫苗高覆盖率背景下麻疹流行特征的变化与免疫策略调整必要性的探讨

目的探讨控制麻疹的策略和措施。方法对芜湖市1996～2005年麻疹的发病情况、麻疹爆发疫情、麻疹疫苗接种率、麻疹疫苗强化免疫等进行综合分析。结果1996～2005年，芜湖市麻疹疫苗报告接种率为98．47％，儿童疫苗免疫后抗体阳性率为95．77％。期间共报告麻疹病例697例，年平均发病率为3．19／10万，其中爆发疫情11起，爆发病例占总数的16．5％，其中有免疫史者占72．3％。与全国大多数地区相似，小于8个月和15岁以上年龄组的发病有增高趋势。根据国内文献资料，近年来全国部分地区13992例麻疹病例中，有麻疹疫苗免疫史的为3921例（28．0％），无免疫史的4753例（34．0％），免疫史不祥的5318例（38．0％）。结论有较好的计划免疫基础并不能避免麻疹的爆发，为达到消除麻疹的目标，除需要扎实开展儿童免疫规划基础工作外，还需对我国现行的麻疹免疫策略及免疫程序进行调整，建立新的成人免疫规划体系，适时研究开发更有效的麻疹疫苗毒株提高疫苗的免疫效力。     

天津市含麻疹成分疫苗接种率和抗体水平评价

目的 对天津市含麻疹成分疫苗（measles containing vaccine,MCV）接种率和健康人群抗体水平进行评价。方法 2012-2014年采用多阶段随机抽样法抽取天津市0～44岁健康人群开展MCV接种率调查和麻疹血清学抗体监测。结果 2006-2013年8个出生队列993名儿童中,含麻疹成分疫苗首剂次（MCV1）接种年龄中位数从2006年8.42月龄提高到2013年的8.15月龄。8月龄及时接种率从2006年50.67%上升到2013年的90.90%。2006-2012年7个出生队列720名儿童中,含麻疹成分疫苗第2剂次MCV2接种年龄中位数从2006年21.99月龄提高到2012年的18.16月龄。18月龄及时接种率从2006年2.67%上升到2012年的71.11%。血清学监测共调查3 147人,年龄为0～44岁,麻疹抗体阳性率90.28%,几何平均浓度（geometric mean concentration,GMC）为912.83 mIU/ml。Logistic回归分析结果显示,<8月龄麻疹易感性最高,其次30～34岁组,OR（95% CI）分别为7.27（3.93～13.46）和3.30（1.67～6.51）。对麻疹抗体阳性率和发病率进行秩相关分析,两者之间存在负相关（r=-0.73,P=0.007）。结论 儿童高免疫覆盖率下,难以阻止成人间的麻疹传播,成人免疫亟待考虑。     

2011 - 2017年湘西自治州麻疹流行病学特征分析

目的 分析2011 - 2017年湘西自治州麻疹流行病学特征。方法 通过中国麻疹信息报告管理系统收集湘西自治州麻疹病例个案的调查数据,采用描述性流行病学方法分析。结果 2011 - 2017年湘西自治州共报告麻疹病例288例,年均发病率1.58/10万;麻疹发病以3 - 6月为发病高峰期;病例以5岁内小年龄的散居儿童为主（85.07%）,尤其以2岁内居多,＜8月龄内儿童及20岁以上成人也占较大比例（35.42%）;男女性别比为1.72∶1;72.83%的8月龄～14岁发病者为含麻疹成分疫苗（MCV）免疫史无或不详; 61.27%的病例出疹前7～21 d有医疗机构就诊或住院史。结论 湘西自治州麻疹发病率呈低发态势,需提高适龄儿童MCV接种率和及时接种率,加强监测和有效处置麻疹疫情,严防院内交叉感染,最终达到消除麻疹目标。     

Measles outbreak in Europe: Susceptibility of infants too young to be immunized

As women vaccinated against measles transfer low amounts of antibodies, an increasing number of infants lack early protection through maternal antibodies until being immunised themselves. This paper reviews the literature on disease burden of measles in the population too young to be immunized according to the respective national recommendations during recent outbreaks in EU and EEA/EFTA countries. In addition, specific control strategies adopted to protect this young population are reviewed. Pubmed, Unbound Medline, Web of Knowledge and the Eurosurveillance database were searched using MESH terms: measles and epidemiology, measles and infants, prevalence of measles, measles and outbreaks and measles and epidemic. Additionally, data from Euvac.net and ECDC were consulted. Databases were searched from January 2001 to September 2011. Fifty-three papers were included in the analysis. The percentage of all measles cases during outbreaks affecting young infants ranged from 0.25% to 83.0%. Specific control strategies were adopted: e.g. administration of the first or second vaccine dose earlier than recommended. Infants younger than 12 months are often involved in measles outbreaks, and advancing the first vaccine dose could reduce the burden of disease. However, immunization before 9 months of age is not systematically recommended because of dysmature humoral immune responses of infants. High coverage and timely administration of the recommended series of vaccines are the most important measures to decrease measles incidence and measles circulation and protect vulnerable infants from infection.     

Measles control efforts in urban Africa complicated by high incidence of measles in the first year of life

A measles vaccination coverage of between 50 and 60% has been achieved in Kinshasa, Zaire, from 1980-1985. During that interval, the annual number of measles cases and the incidence rate of measles reported by a surveillance system remained similar, and measles epidemics occurred in alternating years. The estimated number of measles cases in Kinshasa is 87,600 per year. Of reported measles cases, 27% occurred in children under nine months of age, younger than the recommended age at vaccination. Two results expected in a partially vaccinated population, a reduction in measles incidence greater than the level of vaccination coverage and a shift in the age distribution of measles to older children, have not been observed. Measles control in Kinshasa will require a vaccination coverage of higher than 60%. In addition, given the age-specific risk of measles infection here, a measles vaccine that would be effective when given before nine months of age would be an important element in controlling measles transmission. Because the epidemiology of measles in Kinshasa is a likely consequence of its urban environment, such a vaccine would represent a significant advance toward the control of measles in urban Africa.     

Present anti-measles immunity in Jordan.

The immunity of adults and the prevalence of measles was determined in order to evaluate the adequacy of current measles vaccination policy in Jordan. A total of 307 sera, collected from adults aged 18--40 years, were tested for anti-measles antibodies by ELISA technique. The overall prevalence of anti-measles antibodies was 94.8% and there was no significant difference in the seropositivity rate between males (95.7%) and females (94%). Of the tested adults, 71% were vaccinated and 29% escaped vaccination. In Jordan, measles outbreaks occur periodically and predominantly attack children aged 5--14 years. Our data support introducing the compulsory MMR vaccine in the year 2000 to improve the vaccination coverage of measles; since the optional single dose vaccination has not interrupted the circulation of the measles virus. A second dose of MMR vaccine could be offered to Jordanians either at school entry or at the age of 11--12 years, based on the outcome of the compulsory single dose of MMR vaccine.     

Measles vaccine efficacy during an epidemic in 1998 in the highly vaccinated population of Poland

A measles epidemic with 2255 reported cases occurred in Poland between November 1997 and July 1998, despite high vaccination coverage since the 1980s. Cases occurred at all ages less than 30 years but showed two distinct peaks: young, unvaccinated children born in 1996-1997 and once vaccinated young adults born 1976-1982. The 60% of cases were among persons aged 15 years or more. A cohort study was used to investigate measles vaccine efficacy. The efficacy of a single dose of vaccine exceeded 90% and the efficacy of two doses exceeded 99% in all age-groups. These results demonstrate both the high efficacy of the monovalent measles vaccines used in Poland and the benefit of a second dose of vaccine.