Economic analysis of the 1996-1997 mass measles immunization campaigns in South Africa

To evaluate economic implications of conducting a "catch-up" measles vaccination campaign, we conducted an economic analysis of the 1996-1997 measles immunization campaign in two provinces of South Africa comparing the baseline two-dose routine immunization program to the combined vaccination strategy (routine two-dose immunization program, plus the 1996-1997 campaign). The study findings indicate that the 1996-1997 mass measles immunization campaign was cost-effective in both study provinces, and cost-saving in the province with higher pre-campaign disease incidence and lower routine vaccination coverage. An early investment in effective vaccination strategies that rapidly reduce disease burden apparently results in better returns, both epidemiologically and economically.     

Seroepidemiological evaluation of 1989-91 mass vaccination campaigns against measles, in Italy

In 1989-91 anti-measles vaccination campaigns were conducted in several Italian regions to vaccinate all children aged between 13 months and 10-12 years without a history of measles or measles vaccination. This study was conducted to evaluate serological status after the mass vaccination campaigns. In 1994, capillary blood samples were collected from randomly selected children, aged 2-14 years, living in 13 local health units. Antibody titres were determined by ELISA. Blood spot samples were analysed for 4114 (75.6%) of 5440 selected children. Among the 835 that reported measles before 1990, 806 (96.5%) were immune and of the 2798 vaccinated, 2665 (95.2%) were immune. The Edmoston-Zagreb (E-Z) strain vaccine was associated with a lower level of immunity than the Schwarz (SW) strain. A history of measles identified almost all immune children. Vaccination with the SW strain conferred persistent immunity (at least 5 years) in 98% of vaccinees. The strategy was able to unite natural and induced immunity.     

Effectiveness of pertussis vaccination in New South Wales,Australia, 1996-1998

Pertussis notifications have increased over the past decade in Australia and other industrialised countries. This study estimates the effectiveness of pertussis vaccination in one Australian State (New South Wales, NSW) among children aged less than 14 years, during a period when an Australian whole-cell pertussis vaccine was in routine use. Cases notified with pertussis between 1996 and 1998 and pertussis vaccine coverage estimates from the Australian Childhood Immunisation Register were used. Vaccine effectiveness (VE) was calculated using the screening method, with adjustment for age group, year of disease onset and area of residence. VE was highest (91%) in the youngest age group (8–23 months) and lowest (78%) in the oldest age group (9–13 years). Pertussis vaccination is highly effective at preventing pertussis in NSW children, as measured by notified cases. Ongoing monitoring will be important to evaluate VE following Australia's change to an acellular vaccine based program.     

All-cause mortality trends in Dikgale, rural South Africa, 1996-2003

AIMS: The Dikgale Demographic Surveillance System (DDSS) site, established in 1995, is one of three rural surveillance sites in South Africa. This paper describes detailed mortality patterns of a rural African population in the central region of Limpopo Province. METHODS: These data were based on yearly household visits to collect data on vital events, covering 63, 873 person-years of observation over eight years. RESULTS: Crude mortality was 7.5 per 1,000 person-years (females: 6.9, males: 8.1). Under-1 year and under-5 years mortality was 15.1 and 5.8 per 1,000 person-years, respectively. Life expectancy at birth was 64.3 years (females: 68.1, males: 60.0). For the two four-year periods (1996-9 and 2000-3) under-20 years mortality risk decreased (rate ratio=0.45, 95% CI: 0.25 to 0.80) while 20-49 years mortality risk increased (rate ratio=1.55, 95% CI: 1.10 to 2.20). Multivariate mortality risk for migrants remained relatively constant (0.71, 95% CI: 0.54 to 0.94) across the two four-year periods, but has increased 2.5-fold in all DDSS +50 year-old adults across the two four-year periods. CONCLUSIONS: The DDSS mortality estimates appear to have remained relatively constant while recent mortality estimates for the Agincourt Demographic and Health Surveillance System (ADHSS) site suggest that mortality risk is higher and life expectancy is lower in ADHSS residents. Moreover, DDSS mortality estimates are substantially more favourable compared with provincial and national mortality estimates.     

Effectiveness of influenza vaccination in the elderly in South Africa

This study primarily aimed to estimate the association between influenza vaccination and the occurrence of hospitalization for acute respiratory or cardiovascular diseases, or all-cause death during the influenza season in an elderly population in South Africa. We conducted a nested case-control study using data from a cohort of 45 522 elderly members of a private medical funding organization during the moderate 2004 influenza season. In 1282 (2.8%) subjects the combined outcome occurred and the influenza vaccination rate in controls was 15.4%. After adjustments for measured confounders, vaccination was associated with a statistically significant reduction of 19% (95% confidence interval 3.1-32.9) in the combined outcome. Post-hoc sensitivity analysis of the potential impact of potential healthy user bias showed that confounding, if present, could have caused this finding. Our data were inconclusive regarding the benefits of influenza vaccination in elderly persons in South Africa and given the low vaccine uptake, long-term follow-up is warranted.     

Impact of measles vaccination on childhood mortality in rural Bangladesh

This study examines the impact of measles vaccination on childhood mortality, based on longitudinal data from the Matlab maternal and child health/family planning programme in rural Bangladesh. It analyses the mortality experience of 8135 vaccinated and 8135 randomly matched nonvaccinated children aged 9-60 months, who were observed from March 1982 to October 1985. The results indicate that measles vaccination had a pronounced impact on both short- and long-term survival--the mortality rates for vaccinated children were as much as 46% less than those for nonvaccinated children. Immunization of children aged up to 3 years with measles vaccine appears to improve significantly their subsequent chances of survival. The findings underscore the need to give greater priority to measles vaccination within primary health care programmes in settings such as rural Bangladesh.     

1996年～2005年南阳市麻疹监测情况分析

目的了解南阳市开展麻疹监测以来麻疹流行病学特点,探讨控制麻疹的方法。方法对1996年~2005年麻疹疫情和监测系统运行情况进行分析。结果1996年~2005年全市报告疑似麻疹3562例,临床确诊318例,实验室确诊2186例,年平均报告发病率2.27/10万,麻疹以春季高发,发病年龄以10岁以下为主,29.34%的病例麻疹疫苗(MV)免疫史不详,33.99%的病例无MV免疫史。全市麻疹监测系统运转正常,敏感性较高,麻疹发病率已控制在较低的水平。结论为加速控制麻疹,今后在提高MV常规免疫接种率的同时,要适时开展强化免疫。     

The causal effect of childhood measles vaccination on educational attainment: A mother fixed-effects study in rural South Africa

BackgroundBecause measles vaccination prevents acute measles disease and morbidities secondary to measles, such as undernutrition, blindness, and brain damage, the vaccination may also lead to higher educational attainment. However, there has been little evidence to support this hypothesis at the population level. In this study, we estimate the causal effect of childhood measles vaccination on educational attainment among children born between 1995 and 2000 in South Africa.Methods and findingsWe use longitudinal data on measles vaccination status and school grade attainment among 4783 children. The data were collected by the Wellcome Trust Africa Centre Demographic Information System (ACDIS), which is one of Africa's largest health and demographic surveillance systems. ACDIS is located in a poor, predominantly rural, Zulu-speaking community in KwaZulu-Natal, South Africa. Using mother fixed-effects regression, we compare the school grade attainment of siblings who are discordant in their measles vaccination status but share the same mother and household. This fixed-effects approach controls for confounding due to both observed and unobserved factors that do not vary between siblings, including sibling-invariant mother and household characteristics such as attitudes toward risk, conscientiousness, and aspirations for children. We further control for a range of potential confounders that vary between siblings, such as sex of the child, year of birth, mother's age at child's birth, and birth order. We find that measles vaccination on average increases school grade attainment by 0.188 grades (95% confidence interval, 0.0424–0.334; p = 0.011).ConclusionsMeasles vaccination increased educational attainment in this poor, largely rural community in South Africa. For every five to seven children vaccinated against measles, one additional school grade was gained. The presence of a measles vaccination effect in this community is plausible because (i) measles vaccination prevents measles complications including blindness, brain damage, and undernutrition; (ii) a large number of number of children were at risk of contracting measles because of the comparatively low measles vaccination coverage; and (iii) significant measles transmission occurred in the community where this study took place during the study observation period. Our results demonstrate for the first time that measles vaccination affects human development not only through its health effects but also through its effects on education.     

Impact of hepatitis A vaccination on health care utilization in the United States, 1996-2004

BACKGROUND: Since 1996, hepatitis A vaccine has been recommended for persons at risk for infection and children living in communities with the highest disease rates. In 1999, this recommendation was expanded to include all children in 17 states with high incidence compared to a national baseline period. Reported hepatitis A incidence has decreased substantially since 1999; however, comprehensive data on changes in hospital and outpatient utilization have not been reported. OBJECTIVE: To analyze a health insurance claims database to examine impacts of the hepatitis A vaccination program on medical visits and associated expenditures. METHODS: We conducted a retrospective study of the 1996-2004 Medstat MarketScan databases, which include enrollees of more than 100 health insurance plans offered by approximately 40 large employers each year, using 1996 and 1997 as the pre-vaccination baseline. Trends in rates of medical care visits were analyzed using Poisson regression method. RESULTS: From the pre-vaccination era to 2004, hospitalizations due to hepatitis A declined by 68.5% (from 0.81 to 0.26 per 100,000 population, P<0.001) and ambulatory visits declined by 41.5% (from 12.9 to 7.5 per 100,000 population, P<0.001). Ambulatory visits declined in all age groups, with the greatest declines among children<18 years old. Declines were greater among enrollees who resided in the 17 vaccinating states (58.5%) than those in non-vaccinating states (32.7%, P<0.001). After adjusting to the US population, using data derived from a privately insured population, total estimated direct medical expenditures for hepatitis A-related hospitalizations and ambulatory visits declined by 68.1%, from an average of $29.1 million in 1996 and 1997 to $9.3 million in 2004. CONCLUSIONS: Since the introduction of the hepatitis A vaccination program, hospitalizations, ambulatory visits, and their associated expenditures due to hepatitis A disease have declined substantially among all age groups across the US. Greater declines were seen in the 17 states with vaccination recommendations for hepatitis A.     

湛江市1996～2001年麻疹流行病学调查

目的　调查 1 996～ 2 0 0 1年湛江市麻疹的流行病学情况 ,了解加强免疫对麻疹疫情控制的效果。方法　麻疹加强免疫接种按《广东省 1 998年控制麻疹加强免疫活动实施计划》的方法进行。1 998年 9月中旬对全市范围内 4～ 7岁儿童进行一次麻疹疫苗加强接种 ;1 999年后凡年满 4岁的儿童均接受麻疹疫苗加强免疫接种 ;同时收集 1 996～ 2 0 0 1年各县 (市、区 )与麻疹发病有关的各种流行病学资料进行分析比较。结果　麻疹发病相对集中在 3～ 5月 ,1～ 6岁学龄前儿童为高发人群 ,县级市麻疹发病率比市区高。全市麻疹加强免疫接种前三年 (1 996～ 1 998年 )麻疹发病率为 4 86 / 1 0万 ;麻疹加强免疫接种后三年 (1 999～ 2 0 0 1年 )麻疹发病率为 2 6 8/ 1 0万 ,两者比较差异有显著性 (P <0 0 1 )。结论　麻疹疫苗加强免疫接种后麻疹的发病率明显下降 ,加强免疫对控制麻疹疫情有显著效果     

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.     

2005-2014年中山市麻疹疫情流行病学特征及强化免疫效果评价

目的分析中山市2005-2014年麻疹流行病学特征,评估麻疹疫苗(MeaslesVaccine,MV)强化免疫(Supplementary Immunization Activity,SIA)对麻疹流行病学特征的影响,为制定防控策略提供科学依据。方法采用描述流行病学方法,监测数据进行统计分析。结果MV SIA前、后中山市麻疹年均发病率分别为49.6/10万和4.6/10万,SIA后较SIA前下降了90.7%;SIA前、后病例季节分布无变化,主要集中于4~9月;SIA前、后8月龄~14岁病例各占病例总数的59.8%和35.0%。SIA前、后散居儿童构成比由58.6%上升为65.0%;幼托儿童构成比由12.7%下降为2.5%,差异均有统计学意义(P<0.01)。无免疫史和免疫史不详的病例占病例总数的76.4%。结论 MV SIA能迅速降低麻疹发病率,免疫空白人群是发病的重点人群。建议在做好常规免疫的基础上,每隔3年开展一轮MV SIA,使我市麻疹发病水平维持在一个较低水平,最终达到消除麻疹的目标。     

2010年玉溪市儿童麻疹强化免疫接种率快速评估

目的评估玉溪市2010年麻疹减毒活疫苗(MV)后续强化免疫效果,总结经验,为控制并加快消除麻疹工作进程制定针对性的免疫策略提供依据。方法每县抽取城区和2个乡镇各30名目标儿童进行现场接种率快速评估。结果全市麻疹疫苗强化免疫接种率为99.66%,不同年龄段麻疹疫苗强化免疫接种率均在99.36%以上;不同居住形式麻疹疫苗强化免疫接种率均在97.78%以上,0剂次免疫史该县及外地的儿童均集中分布于8月龄～2岁年龄组。结论玉溪市2010年麻疹疫苗强化免疫达到了预期的目标。加强流动儿童管理,发现并适时消除免疫空白人群是实现2012年消除麻疹目标的工作重点。     

Silicosis screening in surface coal miners--Pennsylvania, 1996-1997

Silicosis is an occupational respiratory disease caused by inhaling respirable crystalline silica dust. Silicosis is irreversible, often progressive (even after exposure has ceased), and potentially fatal. Exposure to silica dust occurs in many occupations, including mining (1). During 1996-1997, surface coal miners at eight sites in Pennsylvania were screened to estimate the prevalence of silicosis, to identify risk factors for silicosis, and to refer miners with a possible diagnosis of silicosis or other conditions for medical evaluation and treatment. This report summarizes the results of the screening, which indicated that an increased prevalence of and risk for silicosis is associated with miners' age and years of drilling experience, and provides recommendations for preventing silicosis among miners.     

Molecular epidemiology of measles viruses in the United States, 1997-2001

From 1997 to 2001, sequence data from 55 clinical specimens were obtained from confirmed measles cases in the United States, representing 21 outbreaks and 34 sporadic cases. Sequence analysis indicated the presence of 11 of the recognized genotypes. The most common genotypes detected were genotype D6, usually identified from imported cases from Europe, and genotype D5, associated with importations from Japan. A number of viruses belonging to genotype D4 were imported from India and Pakistan. Overall, viral genotypes were determined for 13 chains of transmission with an unknown source of virus, and seven different genotypes were identified. Therefore, the diversity of Measles virus genotypes observed in the United States from 1997 to 2001 reflected multiple imported sources of virus and indicated that no strain of measles is endemic in the United States.     

六盘水市1997-2005年麻疹流行病学分析

目的探讨麻疹流行规律,制定相应的防治对策。方法对六盘水市1997-2005年麻疹病例资料进行分析。结果1997-2005年共报告麻疹病例7700例,死亡41例,年平均发病率30.46/10万,年平均病死率0.53%,2003年发病率最高为49.32/10万,2005年发病率最低为0.66/10万。全市各区均有病例发生,全年均有发病,3-6月为发病高峰,发病占总病例数的47.36%(3647/7700),病例以10岁以下儿童为主(占总数的86.36%)。登记完整的932例麻疹病例中有44.85%的病例无免疫史或免疫史不详。2001-2004年六盘水市共报告麻疹暴发疫情25起,只有2起经实验室确诊。结论要预防和控制麻疹应继续做好麻疹疫苗的基础免疫和加强免疫工作,消灭免疫空白点;增加投入,确保冷链系统的正常运转;加强健康教育,使儿童家长认识到计划免疫是防治一些传染病最经济、最有效的手段。     

高校属性对麻疹疫苗接种活动影响的定性调查

了解高校之间麻疹疫苗(measles vaccine,MY)强化免疫活动(supplemental immunization activity,SIA)MV接种率差异的原因,为开展高校疾病防治工作提供参考.方法 采用目的性抽样方法,选择某市10所高校作为研究对象,针对高校MV SIA实施情况进行访谈,定性分析MV接种率差异及其原因.结果 10所高校2017年MV SIA的接种率分别为54%,96%,95%,97%,81%,93%,13%,12%,10%,21%,本科院校远高于专科院校,公办本科院校高于民办,省属公办本科院校高于部属,部属高校之间也存在明显差异.高校的办学层次、办学体制、隶属关系不同,导致医疗资质、风险认知、校地关系等差异,进而影响高校疫苗接种工作的实施.结论 高校的不同属性是导致MV SIA接种率差异的根本原因,建议将高校属性差异纳入免疫规划决策考虑范围,完善高校预防接种政策,加强高校特别是民办高校的风险沟通,改善高校与属地卫生部门的工作关系.     

Measles mortality reduction--West Africa, 1996-2002

The World Health Organization (WHO) estimates that, during 2000, measles accounted for approximately 777,000 deaths worldwide, of which 452,000 (58%) occurred in Africa. In response, in 2000, WHO's African Regional Office (AFRO) adopted a plan to reduce measles mortality >50% by 2005. The plan recommended 1) increasing measles vaccination by strengthening routine health services; 2) providing a second opportunity for measles vaccination for all children, primarily through wide--age-range supplemental immunization activities (SIAs); 3) enhancing measles surveillance; and 4) improving management of measles cases. The initial wide--age-range SIA targets all children aged 9 months-14 years, regardless of history of measles disease or vaccination. Follow-up SIAs are needed 3-5 years after the initial SIA to provide a second opportunity for vaccination to children born since the previous SIA (i.e., those aged 9 months-4 years). During the 1990s, the countries of the Americas and seven countries in southern Africa used this strategy to reduce the number of measles deaths to near zero. This report describes the recent implementation of this strategy in three West African countries, where reported measles cases declined 83%-97% during the first year after SIAs. Successful implementation of this strategy by other African countries should result in achieving the goal of >50% reduction in measles mortality by 2005.     

Impact of measles outbreak response vaccination campaign in Dar es Salaam,Tanzania

We assessed the impact of a measles outbreak response vaccination campaign (ORV) in Dar es Salaam, Tanzania. Age-specific incidence rates were calculated before and after the ORV. Incidence rate ratios for the two time periods were compared and used to estimate expected cases and deaths prevented by ORV. The ratio of measles incidence rates in the age groups targeted and not targeted by ORV decreased from 5.8 prior to ORV to 1.8 (p < 0.0001) after; 506 measles cases and 18 measles deaths were likely averted. These results support the need for revised recommendations concerning ORV in general settings in Africa.