Measles epidemiology and outbreak response immunization in a rural community in Peru.

Only limited data are available on the impact of measles outbreak response immunization (ORI) in developing countries. We conducted a community survey in Espindola, a rural border community in northern Peru, following a measles outbreak and subsequent ORI to study the epidemiology and impact of the outbreak and to evaluate the costs and benefits of measles ORI. During the outbreak, 150 of the 553 Espindola residents developed clinical cases of measles. Adults accounted for 44.0% of cases, and were frequently identified as primary cases. The attack rate among all susceptible people was 45.5% and was highest (61.2%) for the 16-20 year age group. Among adults, significant risk factors for developing measles included being aged 16-20 years (relative risk [RR] = 3.06, 95% CI = 2.08, 4.49) and being male (RR = 1.73, 95% CI = 1.11, 2.71). Among serologically confirmed cases, 60.7% developed diarrhoea and 32.1% pneumonia. The overall case-fatality rate was 3.3%, but reached 19.1% in the 0-23-month age group. Failure to reach children through either routine immunization or national campaigns made this community vulnerable to the severe and extensive impact of measles virus importation. The ORI campaign targeted non-measles case children aged 6 months to 15 years, regardless of their previous immunization status, and was effective in terminating this measles outbreak and in preventing morbidity, loss of livelihood and death despite the involvement of large numbers of adults in measles transmission. The last measles case occurred within 3 weeks of completing ORI. The ORI campaign, which would have cost approximately US$ 3000 in 1998, saved as many as 1155 person-days of work among 77 adults, prevented an estimated 87 cases of diarrhoea and 46 cases of pneumonia, and averted 5 deaths.     

A persistent outbreak of measles despite appropriate prevention and control measures

From January 4 to May 13, 1985, an outbreak of 137 cases of measles occurred in Montana and persisted for 12 generations of spread. A total of 114 cases occurred on the Blackfeet Indian reservation in northwest Montana. Of the 137 cases, 82 (59.9%) were in school-aged children (aged 5-19 years). Of the 114 cases on the reservation, 108 (94.7%) were classified as programmatically nonpreventable. A total of 64 (82.1%) of the 78 patients on the reservation who were born after 1956 and were above the recommended age at vaccination had a history of adequate measles vaccination. Additionally, an audit of immunization records at the schools in Browning, Montana, where most of the cases occurred, showed that 98.7% of students were appropriately vaccinated. A retrospective cohort study in the Browning schools failed to identify age at vaccination or time since vaccination as significant risk factors for vaccine failure. Overall vaccine efficacy was 96.9% (95% confidence interval = 89.5-98.2%). None of 80 Browning students who were vaccinated at less than 12 months of age and revaccinated at 15 months of age or older became infected. A case-control study showed a significant association between attendance at Browning basketball games and infection early in the outbreak. This outbreak suggests that measles transmission may persist in some settings despite appropriate implementation of the current measles elimination strategy.     

巴马县2013年麻疹爆发疫情流行病学调查

目的了解和分析巴马县2013年麻疹爆发疫情的流行病学特征和发生原因,为消除麻疹提供参考。方法对疫情进行流行病学调查和分析。结果此次麻疹爆发疫情持续5个月,共报告麻疹528例,发病率为232.99/10万,死亡1例。〈6岁病例数占总病例数的82.76%。结论当地免疫规划疫苗接种率低、瞒报迟报疫情是此次麻疹疫情爆发的主要原因。     

Investigation of an outbreak of nosocomial infection due to a multiply drug-resistant strain of Pseudomonas aeruginosa.

A nosocomial outbreak of Pseudomonas aeruginosa infections which occurred in the Urology Service of a large city hospital was studied. A case-control methodology was used to analyse patients' characteristics and the main risk factors of all cases with a positive culture during the period between March 1987 and March 1988. The usefulness of factor analysis in the definition of a case was examined. There were 74 infections of which 35 (47.3%), had a nosocomial origin. The outbreak took place in December 1987, with a peak incidence of infections of 10.5%, compared with a 2.2% frequency during the preceding months (P less than 0.005). Six of the nine infections occurring in that month, were caused by strains resistant to ticarcillin and gentamicin. The epidemic cases had longer hospital stays than the non-epidemic cases (P less than 0.038) and occurred more frequently in a specific area of the hospital (P less than 0.001). The odds ratio for resistance to gentamicin was 15 (P less than 0.018) and that of resistance to ticarcillin, 127 (P less than 0.0001). Our results suggest that inaccurate case definitions may produce misleading conclusions. Factor analysis appears to be a useful analytical tool when defining a case.     

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.     

河北省沧县2006-2007年麻疹流行病学调查与预防对策

目的了解河北省沧县麻疹的流行规律和流行现状，为制定预防对策提供科学依据。方法对2006-2007年沧县86例麻疹病例进行流行病学分析。结果该县2年内报告麻疹86例，总发病率12．92／10万，年平均发病率为6．46／10万。2007年比2006年发病上升了9．76％，2年内无报告死亡病例，无暴发流行。2年内发病呈明显季节性，以冬春季3—6月和12月为主，占83．72％。年龄以1岁以内和15～30岁为主，占60．47％。在地区分布上，以散居儿童、幼托儿童、学生、农民为主，占91．86％。结论沧县麻疹发病率有明显上升的趋势，呈波浪式散在发生，无暴发流行。发病年龄呈双向移位。因此，在做好基础免疫接种的同时，应加大1岁以内和大年龄组的麻疹监测和免疫接种、复种、补种工作，以提高整个人群的麻疹免疫抗体水平，降低麻疹发病率。     

Measles outbreak in a vaccinated school population: epidemiology, chains of transmission and the role of vaccine failures

An outbreak of measles occurred in a high school with a documented vaccination level of 98 per cent. Nineteen (70 per cent) of the cases were students who had histories of measles vaccination at 12 months of age or older and are therefore considered vaccine failures. Persons who were unimmunized or immunized at less than 12 months of age had substantially higher attack rates compared to those immunized on or after 12 months of age. Vaccine failures among apparently adequately vaccinated individuals were sources of infection for at least 48 per cent of the cases in the outbreak. There was no evidence to suggest that waning immunity was a contributing factor among the vaccine failures. Close contact with cases of measles in the high school, source or provider of vaccine, sharing common activities or classes with cases, and verification of the vaccination history were not significant risk factors in the outbreak. The outbreak subsided spontaneously after four generations of illness in the school and demonstrates that when measles is introduced in a highly vaccinated population, vaccine failures may play some role in transmission but that such transmission is not usually sustained.     

Measles epidemic in Harare, Zimbabwe, despite high measles immunization coverage rates.

Despite rapidly increasing measles immunization coverage in Harare city, measles remains endemic, and regular outbreaks occur. The most recent occurred in 1988, when the measles immunization coverage was 83%. We have carried out a retrospective study of the clinical and epidemiological features of this outbreak to assess whether the present immunization policy needs to be changed. Of 4357 cases of measles seen at primary health care centres and hospitals in Harare during the outbreak, 1399 (32%) were severe or involved complications that required hospital admission. The peak incidence occurred among under-2-year-olds, followed by that among 5-7-year-olds. Poor nutritional status was significantly more frequent among children who were hospitalized and among those who died. A total of 59% of all cases aged 9-59 months had documented evidence of measles immunization. The most frequent complications, which occurred most often among under-5-year-olds, were diarrhoea with dehydration, pneumonia, laryngotracheobronchitis, and convulsions, which together affected 56% of hospitalized cases. The hospital case fatality rate was low (1.43%). In Harare, measles transmission remains a problem, despite high measles immunization coverage rates; the failure rate for the standard Schwarz measles vaccine also appears to be high. There is a need to reduce the number of measles cases among under-9-month-olds and young children. Further studies into alternative measles vaccines and schedules are required.     

一起缅甸输入新型麻疹病毒(d11基因型)引发暴发疫情的调查分析

目的 研究缅甸输入新型麻疹病毒(d11基因型)导致暴发疫情的相关因素及阻断传播的有效策略和措施.方法 应用流行病学方法进行现场暴发调查.结果 云南省孟连县4个乡镇(66%)报告麻疹15例,6月龄至5岁儿童7例,2例有麻疹疫苗(MV)免疫史;21～49岁8例,免疫史均不详.缅甸入境人员就诊14例,年龄10月龄至13岁,仅1例接种过MV.除1例缅甸病例未采到标本外,其余28例患者麻疹IgM抗体均为阳性,有6例标本检测到麻疹病毒核酸,扩增后测序为麻疹病毒d11基因型,为缅甸输入的d11基因型野病毒.MV接种率和抗体水平调查184人,接种率61.96%,麻疹IgG抗体阳性率87.50%.及时开展MV应急接种,麻疹疫情得到有效控制.结论 境外输入麻疹病例可以引发境内麻疹流行,预示云南省消除麻疹面临巨大困难和挑战;应急接种MV可以阻断传播,说明目前使用的MV对预防d11基因型麻疹病毒感染同样有效.

Abstract：

Objective To study the relevant factors on an measles outbreak caused by imported new virus (d11 genotype)from Myanmar and to develop effective strategies and measures.Methods On-site investigation on the outbreak was carried out. Results There were four townships (66%) in Menglian county reported 15 cases of measles, with 7 cases aged 6 months to 5 years old, 2 cases with the history of measles vaccination (MV). Another 8 cases were 21 to 49 year-olds but their histories on immunization were unclear. 14 of the measles cases with Myanmar citizenship came to China for treatment. They were aged 10 months to 13 years old, with only one case had ever received MV vaccination. For all the 29 cases, except for one case who did not adopt the sample case of Myanmar, the remaining 28 patients were positive for measles IgM antibodies. 6 cases of measles virus RNA were detected in the amplified sequence which showed genotype d11, and was considered Myanmar imported wild virus. 184 people received the MV inoculation, with a rate of 61.96% and the serum samples showed a measles IgG antibody positive rate of 87.50%. Manner MV emergency vaccination was carried out timely in that county so the measles outbreak was effectively controlled.Conclusion Imported measles cases from foreign countries might lead to epidemic, indicating the difficulty and challenge in the elimination of measles in our province. Emergent vaccination of MV could interrupt the transmission of the disease. Our experience showed that MV was effective in the prevention of d11 genotypes measles infection in the area.     

Measles outbreaks affecting children in Jewish ultra-orthodox communities in Jerusalem

In 2003 and 2004 two measles outbreaks occurred in Jewish ultra-orthodox communities in Jerusalem. The index case of the first outbreak (March 2003) was a 2-year-old unvaccinated child from Switzerland. Within 5 months, 107 cases (mean age 8.3+/-7.5 years) emerged in three crowded neighbourhoods. The first cases of the second outbreak (June 2004) were in three girls aged 4-5 years in one kindergarten in another community. By November 2004, 117 cases (mean age 7.3+/-6.5 years) occurred. The virus genotypes were D8 and D4 respectively. Altogether, 96 households accounted for the two outbreaks, with two or more patients per family in 79% of cases. Most cases (91.5%) were unvaccinated. Immunization coverage was lower in outbreak than in non-outbreak neighbourhoods (88.3% vs. 90.3%, P=0.001). Controlling the outbreaks necessitated a culture-sensitive approach, and targeted efforts increased MMR vaccine coverage (first dose) to 95.2%. Despite high national immunization coverage (94-95%), special attention to specific sub-populations is essential.     

Epidemiology of measles in Taiwan: dynamics of transmission and timeliness of reporting during an epidemic in 1988-9.

We analysed nation-wide reported measles cases during the 1988-9 epidemic and found that longer duration and wider spread were two major characteristics of the outbreak. All the 22 county/city index cases were reported with a delay of > 4 days and 64% were aged 5-14 years. This epidemic occurred mainly among 5-14-year-old school-children (59%), infants under 1 year (19%), and pre-school children (18%). The overall attack rate was 0.63 cases per 10,000 population, with the highest attack rate (7.4 cases per 10,000 population) occurring in infants. Among 280 confirmed cases < 15 months of age, 9-month-old infants (42 cases) had a higher risk of measles and peaked at 10 months (49 cases). This epidemic started in March 1988 among 5-9-year-old children in the northern suburban area, then spread to Taipei City and neighbouring counties or cities. It continued to spread from the northern to southern and western areas during the summer vacation and New Year holidays. Multiple logistic regression analysis showed that the delay of measles reporting was strongly associated with the cases infected early in the epidemic (OR = 6.9, P < 0.001) and reported from teaching hospitals (OR = 2.6, P < 0.001). The reappearance of high attack rates among 5-9-year-old children in the 1985 and 1988-9 measles epidemics in Taiwan indicated the persistence of pockets of susceptible individuals even after mass immunization.     

A hospital-associated measles outbreak among individuals not targeted for vaccination in eastern China, 2014

BackgroundAn outbreak of measles occurred in early 2014 among individuals not targeted for vaccination—adults, and infants too young to vaccinate, in Xiangshan County, Zhejiang Province, in eastern China.ObjectiveWe conducted an investigation to identify risk factors responsible for this outbreak and to provide evidence-based recommendations for measles elimination strategies in China.MethodsMeasles was diagnosed using national standard case definitions. In a case-control study, 20 randomly selected measles patients were matched with controls selected from the same village or community as each case in a 1:2 case-to-control ratio. Controls were matched on age, within 5 years, and gender. We compared exposure histories during the 7–21 days before rash onset of the case and the same time period for the matched controls. We also conducted a measles antibody seroprevalence survey of a convenient sample of residual serum obtained from healthy patients during routine care in a hospital.ResultsThe outbreak consisted of 45 measles cases, with an attack rate of 8.9/100,000 total population. Among cases, 91.1% (41/45) were adults (ranged 23–51 years) who had unknown vaccination histories; the other cases were infants younger than 8 months of age. The case-control study showed major risk factors to be a visit to Hospital X (OR_MH = 7.3, 95% CI: 1.8–30.7) and treatment in an IV room in Hospital X (OR_MH = 11.0, 95% CI: 1.3–96.1). The seroprevalence survey showed that 88.8% of adults had measles IgG antibodies, and that 100% of children 2–19 years of age were seropositive.ConclusionsThe outbreak was primarily among age groups not targeted for vaccination—primarily adults, but with some children too young to vaccinate. Visiting a hospital was the major risk factor for measles transmission. We conclude that in addition to maintaining high 2-dose coverage with measles vaccine, working with hospital infection control programs to implement evidence-based strategies to prevent or limit hospital transmission is an important action for eliminating measles in eastern China.     

Control of a measles outbreak in an elementary school. Baltimore County,Md. 1975.

Between April 18 and May 20, 1975, 16 cases of measles occurred in pupils in an elementary school in Baltimore County, Md., and 1 case occurred in a sibling at a junior high school. Measles was serologically confirmed in 16 of these pupils. Attack rates were determined by grade and by vaccine status. The measles attack rate was 2.1 percent for the 377 children who had been given measles vaccine at 1 year of age or later. The rates were 27.8 percent (13 times higher) for those vaccinated at less than 10 months of age and 20.0 percent (10 times higher) for those with no definite history of vaccine. The higher attack rates for children who were vaccinated only before 10 months of age supports the 1972 recommendation of the Public Health Service Advisory Committee on Immunization Practices that children vaccinated before this age need to be revaccinated with live measles virus vaccine to assure full protection. The finding that 2 of 10 children with a history of measles became ill during the outbreak suggests that such histories are not a totally reliable indicator of immunity. Containment of the outbreak was attributed to the high level of immunity in the community and prompt initiation of control measures.     

A community hospital outbreak of legionellosis. Transmission by potable hot water

Seven cases of nosocomial legionellosis occurred between February and September 1982 in a small community hospital in Upstate New York. All seven were cases of Legionella pneumophila serogroup 1; six were hospital patients and one a hospital employee. None of the cases died. During the peak of the outbreak, the incidence of nosocomial legionellosis was 1.2 cases per 100 patient discharges. An epidemiologic comparison of the six patient cases with 21 matched patient controls suggested that longer hospital stay (chi 1(2) = 24.2, p less than 0.001) and the proximity of patients' rooms to ward showers (chi 1(2) = 4.4, p less than 0.04) were significant risk factors for acquiring legionellosis. An environmental investigation demonstrated that the ward showers and the hospital hot water system were contaminated with L. pneumophila serogroup 1. Monoclonal antibody subtyping performed on isolates obtained during the outbreak investigation confirmed that the hot water system and patient isolates had an identical pattern of reactivity. The outbreak demonstrates that legionellosis can be a significant cause of nosocomial pneumonia in a community hospital and that transmission can occur from contaminated potable hot water sources, potentially via shower aerosols.     

Measles outbreak associated with an imported case in an infant--Alabama, 2002

Local transmission of measles is rare in the United States. Since 1997, the majority of measles outbreaks have been caused by imported cases. During October 19-November 15, 2002, an outbreak of 13 confirmed cases of measles occurred, with exposure in Alabama; 11 cases were among day care attendees who had not yet been vaccinated for measles. This was the largest outbreak of measles in the United States since 1999. In response to this outbreak, the Alabama Department of Public Health (ADPH) and CDC conducted an epidemiologic investigation that determined the outbreak was initiated by an imported case in an infant aged 9 months who had returned recently from the Philippines. Health-care providers should continue to include measles in differential diagnoses for febrile rash illnesses in infants, particularly those with recent travel to areas where measles is endemic.     

An explosive point-source measles outbreak in a highly vaccinated population. Modes of transmission and risk factors for disease

In 1985, 69 secondary cases, all in one generation, occurred in an Illinois high school after exposure to a vigorously coughing index case. The school's 1,873 students had a pre-outbreak vaccination level of 99.7% by school records. The authors studied the mode of transmission and the risk factors for disease in this unusual outbreak. There were no school assemblies and little or no air recirculation during the schooldays that exposure occurred. Contact interviews were completed with 58 secondary cases (84%); only 11 secondary cases (19%) of these may have had exposure to the index case in the classrooms, buses, or out of school. With the use of the Reed-Frost epidemic model, only 22-65% of the secondary cases were likely to have had at least one person-to-person contact with the index case during class exchanges, suggesting that this mode of transmission alone could not explain this outbreak. A comparison of the first 45 cases and 90 matched controls suggested that cases were less likely than controls to have provider-verifiable school vaccination records (odds ratio (OR) = 8.1) and more likely to have been vaccinated at less than age 12 months (OR = 8.6) or at age 12-14 months (OR = 7.0). Despite high vaccination levels, explosive measles outbreaks may occur in secondary schools due to 1) airborne measles transmission, 2) high contact rates, 3) inaccurate school vaccination records, or 4) inadequate immunity from vaccinations at younger ages.     

Outbreak of measles in Kielce--June 2001

Kielce area has had a very low incidence of measles. The outbreak of measles was reported in June 2001 and included a cumulative number of 12 cases, of whom 11 have been lab confirmed. Nine cases belonged to Gypsy community and were less than 16 years of age. Remaining 3 cases were medical care workers of age 29-31. None of the children involved in the outbreak have been previously vaccinated against measles.     

The epidemiology of measles in a partially vaccinated population in an African city: implications for immunization programs

A large outbreak of measles was reported in Pointe-Noire, Congo, between October 1984 and March 1985. An investigation was conducted to determine the epidemiology of measles in this community in which, in 1985, 54% of the children 12-23 months of age had documented evidence of vaccination against measles. The investigation included hospital and clinic record reviews and a community survey. Measles has been continuously transmitted in Pointe-Noire since at least 1979, with seasonal epidemics. In early 1984, the expected epidemic did not occur, and at least 1,000 measles hospital admissions and 100 measles deaths were prevented. Between October 1984 and March 1985, 1,942 measles cases were hospitalized, of which 306 (15.8%) died. During the epidemic, the proportion of nonpreventable cases (cases occurring before nine months of age) was 17%, reflecting the change in age distribution of measles cases in childhood since the immunization program started in Pointe-Noire in 1982. From the community survey, it was estimated that 13% of all children under age five years acquired measles in Pointe-Noire in 1985. Vaccine efficacy was calculated from community and hospital samples to be between 78% and 87%. Our findings suggest that increasing vaccination coverage levels to well above 50% is necessary to substantially reduce measles morbidity and mortality in African cities.     

连云港市2008~2009年麻疹暴发流行病学调查

[目的]了解连云港市麻疹暴发的流行病学特征,为制订麻疹防控策略提供科学依据。[方法]采用描述性流行病学方法进行麻疹疫情分析,血清学检验方法进行麻疹病例的实验室诊断,对麻疹高发村开展麻疹疫苗效力调查。[结果]2008年9月1日～2009年7月1日间连云港市局部地区发生了麻疹暴发流行,病例数为1234例,主要集中在3个县:灌云县(40.94/10万)、灌南县(44.15/10万)、赣榆县(24.34/10万)。在0～5岁儿童发病为多,占1234例麻疹病例的71.39%,其中8～24月龄婴幼儿发病占0～5岁组病例的69.92%。实验室诊断病例占91.65%;麻疹疫苗效力:下口村0～60月龄儿童为56.52%、元邦村为75.95%,平均为64.29%;麻疹疫苗调查平均接种率为58.33%。[结论]部分适龄儿童的漏种或未及时接种麻疹疫苗是连云港市3个县2008年9月～2009年7月间麻疹暴发流行的主要原因,因此应提高适龄儿童麻疹接种的及时性和接种率,确保2012年控制和消除麻疹目标的实现。     

Measles transmission among adults with spread to children during an outbreak: Implications for measles elimination in China, 2014

IntroductionFollowing implementation of China's 2006–2012 Action Plan for measles elimination, which led to a nadir of measles in 2012, a resurgence started in 2013 that continued into 2014. Measles typically is a disease that mainly affects children. We investigated a community outbreak in 2014 with measles virus transmission among adults without children serving as virus reservoirs. Our investigation highlights adult susceptibility to measles.MethodsWe conducted a retrospective active case search, and analyzed confirmed case data to describe person, place, and time characteristics of the outbreak. All individuals with measles with onset during the first 2 months of the outbreak were interviewed face-to-face to determine source(s) of infection and transmission route (from whom and to whom).ResultsAmong the 280 cases, 220 (77.6%) were among ≥20-year-old adults, 24 (8.6%) were among 8–23 month olds, 22 (7.9%) were among <8-month-old infants, and the remaining 14 (5.9%) were among 2–19 year olds. Of the 83 cases in the early stage of the outbreak, 41 (49.4%) were acquired in the community, 24 (28.9%) were acquired nosocomially, 13 (15.7%) were acquired by family contact, and 5 were imported. Among 44 clearly determined transmission linkages, 37 (84.1%) were adult to other age-group (these include 29 adult-to-adult, seven adult-to-child, and one adult-to-infant), six were from infants to adult and children, and one was child-to-child. Outbreak response immunization activities were implemented by non-selective supplementary immunization activities, with 51.3% of targeted 5–19-year-old children and adolescents, and 30.2% of targeted 20–49-year-old adults being vaccinated.ConclusionsDespite high population immunity among children and adolescents following three rounds of measles vaccine supplementary immunization activities, sustained measles virus transmission still occurred among adults in this community. Adult measles immunity gaps might threaten measles elimination, highlighting the importance targeting susceptible adults during outbreak response immunization.