Assessment of the epidemiology and burden of measles in Southern Mozambique

Measles has been a major killer among vaccine-preventable diseases in children < 5 years of age in developing countries. Despite progress in global efforts to reduce mortality, measles remains a public health problem. Hospital-based measles surveillance was conducted in Manhica, Mozambique (July 2001-September 2004). Suspected cases and community-based controls were enrolled, and blood was collected for immunoglobulin M (IgM) confirmation. Two hundred fifty-three suspected cases and 477 controls were enrolled, with 85% (216 of 253) cases reported during a measles outbreak. Measles-IgM confirmation was 30% among suspected cases and 5% in controls. Fifty-eight percent (14 of 24) of laboratory-confirmed cases had records indicating previous measles vaccination. Mortality was 3% (8 of 246) among cases and 1% among controls (6 of 426). Forty-five percent (33 of 74) of cases were < 24 months of age and 22% occurred in infants < 9 months of age and were associated with a high case-fatality rate (25%). Our data suggest that improved diagnostics, new tools to protect infants < 9 months of age, and a supplemental dose of measles vaccine could assist measles control.     

Stability of the age distribution of measles cases over time during outbreaks in Bangladesh, 2004-2006

Despite recommendations from WHO to conduct measles outbreak response vaccination campaigns based on the age distribution of cases at the beginning of an outbreak, few data exist to specifically examine whether the age distribution of cases remains constant over time in a measles outbreak. This analysis explores this question with use of measles outbreak surveillance data from Bangladesh from the period 2004-2006. Pearson χ(2) tests were conducted of age distributions over 2 periods during 41 large laboratory-confirmed measles outbreaks. Statistically significant changes in age distribution over time were observed in 24% of the outbreaks. No single pattern was detected in the shifts in age distribution; however, an increase in the proportion of cases occurring among infants <9 months of age was evident in 6 outbreaks. These findings suggest a need to consider the possibility of a shift in the age distribution over time when planning an outbreak response vaccination campaign.     

Outbreaks caused by parvovirus B19 in three Portuguese schools

This paper reports the study of outbreaks of an acute exanthematous disease among children of three schools in the municipality of Braga (Portugal). Laboratory tests were performed for five cases, showing that the disease was not due to infection by measles or rubella virus, and infection with parvovirus B19 was confirmed. There were 41 cases in children: 12 in the kindergarten, 17 in the secondary school and 12 in the primary school. There was only one case in a staff member, who worked in the kindergarten. Eight cases were identified among household contacts; two of them were brothers, one from the kindergarten and another from the secondary school, where the outbreak occurred after the kindergarten outbreak. The estimated values of the basic reproduction number R0 were very low and it is very likely that asymptomatic infectious cases have occurred. The local health authority produced written documents and met with staff members and parents. Primary healthcare facilities and the obstetric department of the local hospital were also informed. As we are approaching the elimination of measles in Portugal and the rest of Europe, with very high vaccine coverage, it is very likely that a high proportion of infectious non-vesicular exanthemas will be due to B19 infections. This is to be taken into account in the design and conduct of surveillance activities, in the context of measles and rubella elimination programmes.     

A large rubella outbreak, Romania--2003

Romania experienced a large rubella outbreak in 2002-03, with more than 115,000 reported cases nationwide, and an incidence of 531 reported cases per 100,000 population. The incidence was highest in children of school age. The cohorts of adolescent girls vaccinated in 1998 and 2002 (when a rubella-containing vaccine was available) had significantly lower incidence rates (p<0.001) compared with those in boys in the same age groups who were not vaccinated. In 2003, of the 150 suspected congenital rubella syndrome (CRS) cases reported, seven (4.6%) were confirmed by positive rubella IgM antibodies. In the absence of available rubella containing vaccine for outbreak control, an outbreak response plan to improve the detection of cases and to limit rubella virus transmission was developed. The following activities were conducted: surveillance of pregnant women with suspected rubella or history of exposure to rubella virus was implemented, with follow up of pregnancy outcomes; surveillance for CRS was strengthened; existing infection control guidelines to prevent disease transmission within healthcare facilities were reinforced; and a communication plan was developed. In May 2004, Romania is introducing measles, mumps and rubella (MMR) vaccine for routine vaccination of children aged 12 to 15 months, while continuing vaccination of girls in the 8th grade of school (13-14 years of age) with rubella-only vaccine.     

Interruption of measles transmission in Gipuzkoa (Basque Country), Spain

Measles vaccine was introduced in Gipuzkoa (Basque country, Spain) in 1978 and was replaced by the measles, mumps, and rubella (MMR) vaccine for children aged 12-15 months in 1981. A second dose of the MMR vaccine was introduced in 1992. Both doses of the MMR vaccine were well accepted by the population and high coverage was achieved (95% and 91% for the first and second doses respectively for the period 1993-2002). Measles virus circulation was interrupted in the second half of the 1990s: no cases of indigenous measles were notified between 1998 and 2003, and only imported cases have been confirmed during this period. These data indicate that the measles vaccination programme implemented has been effective. Nevertheless, to avoid measles outbreaks following viral introduction, high MMR vaccine coverage levels for the two doses have to be maintained (>95%).     

A 24-year review on the epidemiology and control of measles in Singapore, 1981-2004

The objective of our paper is to review the epidemiology of measles in Singapore and the impact of the measles vaccination program on the control of measles. Our review will form the basis for a critical appraisal of our future measles control program. We analyzed the trend of reported measles cases in relationship to measles vaccination coverage from 1981 to 2004 using routine measles notifications and measles vaccination data submitted to the Ministry of Health and the National Immunization Registry, respectively. We determined the measles vaccine efficacy using data from epidemiological investigations of reported institutional measles outbreaks. The herd immunity of the population against measles was accessed through three seroepidemiological surveys that we conducted in 1989/1990, 1993 and 1998. In addition, we collected blood specimens from every clinically diagnosed case of measles notified to the Ministry in 1998/1999 to for measles-specific IgM antibodies in order to evaluate the proportion of clinically diagnosed cases of measles that were laboratory confirmed. The incidence of measles has decreased significantly since 1981 as a result of increased vaccination coverage of 89-93% following implementation of compulsory measles vaccination in 1985. However, resurgences still occurred in 1992/1993 and 1997. With the implementation of the two-dose measles vaccination schedule, the annual number of laboratory confirmed cases of measles to date has been less than 150. Vaccine efficacy of the trivalent MMR vaccine based on institutional outbreak investigations was consistently above 92%. We also found that the overall seroprevalence of the population to measles has decreased from approximately 91.5% in 1989/1990 to 1993 to 77.9% in 1998 (mainly in children < 4 years old) and that only 7% of clinically notified cases of measles were serologically confirmed to be positive for measles. Achieving a vaccination coverage of more than 95%, tightening our MMR vaccine delivery system and strengthening surveillance of measles are essential components which must be addressed in order to interrupt measles transmission in Singapore.     

Diagnostic challenges and pockets of susceptibility identified during a measles outbreak,Luxembourg, 2019

Luxembourg was among the first countries in the World Health Organization (WHO) European Region documenting interruption of endemic measles transmission, but an increased incidence was registered in spring 2019. The outbreak started with an unvaccinated student who had been to a winter sports resort in a neighbouring country, where a measles outbreak was ongoing. Subsequently, 12 secondary and two tertiary cases were confirmed among students from the same school, relatives and healthcare workers, as well as six probably unrelated cases. Only 11 cases initially fulfilled the WHO definition for suspected measles cases. Fourteen of 20 cases with information on country of birth and the majority of unvaccinated cases (10/12) were born outside of Luxembourg. Measles IgM antibody results were available for 16 of the confirmed cases, and five of the eight IgM negative cases had been vaccinated at least once. All 21 cases were PCR positive, but for three previously vaccinated cases with multiple specimen types, at least one of these samples was negative. The outbreak highlighted diagnostic challenges from clinical and laboratory perspectives in a measles elimination setting and showed that people born abroad and commuters may represent important pockets of susceptible people in Luxembourg.     

娄底市麻疹流行病学分析

目的 详细了解娄底市麻疹流行情况及其流行病学特征,为有效控制麻疹提供科学依据供各级领导和专业人员参考.方法 全部资料录入或导入MS-Excel 进行统计并作图,比较分析用SPSS 13.0版完成.结果 1978～2005年共报告麻疹31 963例,年均发病率31.18/10万, 历年发病率与接种率呈明显负相关(r-0.802,P＜0.01).发病从高到低后回升,可分为3个时段,年均发病率分别为95.94/10万、4.06/10万和9.66/10万,各时段各县市区发病率差异极其显著(χ254 636.36,P＜0.000 1).整个发病趋势第1时段形成3个高峰之后,1987～2000年一路走低,其中1993～1994年形成一个低谷,至2004年再度形成一个相对高峰.共报告麻疹死亡76例,病死率0.24%.1991～2005年整个发病季节集中在3～6月,但在2004年回升高发时发病高峰在2～4月.2001～2005年麻疹发病数男女性别比为1.94: 1,年龄分布最小23日,最大60岁,5岁以下儿童占56.89%,散居儿童发病数占总数的53.87%,其发病率与幼托儿童和学生比较有统计学意义(χ2921.46,P＜0.000 1).结论 娄底市麻疹发病率总体下降89.93%,但近年有上升趋势,上升原因主要为计划免疫滑坡,存在免疫空白人群.     

Molecular epidemiology of measles in India, 2005-2010

Measles is a childhood disease that causes great morbidity and mortality in India and worldwide. Because measles surveillance in India is in its infancy, there is a paucity of countrywide data on circulating Measles virus genotypes. This study was conducted in 21 of 28 States and 2 of 7 Union Territories of India by MeaslesNetIndia, a national network of 27 centers and sentinel practitioners. MeaslesNetIndia investigated 52 measles outbreaks in geographically representative areas from 2005 through June 2010. All outbreaks were serologically confirmed by detection of antimeasles virus immunoglobulin M (IgM) antibodies in serum or oral fluid samples. Molecular studies, using World Health Organization (WHO)-recommended protocols obtained 203 N-gene, 40 H-gene, and 4 M-gene sequences during this period. Measles genotypes D4, D7, and D8 were found to be circulating in various parts of India during the study period. Further phylogenetic analysis revealed 4 lineages of Indian D8 genotypes: D8a, D8b, D8c, and D8d. This study generated a large, countrywide sequence database that can form the baseline for future molecular studies on measles virus transmission pathways in India. This study has created support and capabilities for countrywide measles molecular surveillance that must be carried forward.     

Interruption of indigenous measles transmission in Bolivia since October 2000

Measles incidence in Bolivia declined after the introduction of campaign strategies in the 1980s. From 1990 to 1993, the peak incidence of measles (59 cases/100,000 population) was in 1992. In 1994, after the goal of interruption of measles transmission was adopted, a national vaccination campaign targeting children <15 years old was conducted and achieved 96% coverage. During 1995-1997, cases declined, although routine coverage was <90% in most years. During 1998-2000, a nationwide epidemic occurred among 2567 case-patients, most of whom were unvaccinated. A national vaccination campaign, with strong supervision, was conducted during November and December 1999 and targeted areas with low coverage. Only 122 cases were confirmed in 2000, with the last confirmed case occurring in October. Crucial to the control of the outbreak were sufficient resources and political support, intensive local planning, door-to-door vaccination with strict supervision, and rapid house-to-house coverage monitoring that improved accountability at the local level and timely and thorough outbreak investigations.     

Measles outbreak in Venezuela: a new challenge to postelimination surveillance and control?

The circulation of wild measles virus was interrupted in Venezuela in February 2007 after the catch-up vaccination (1994) and monitoring (1998) and in response to the measles outbreak in 2001. Traditionally, the routine coverage with measles-mumps-rubella vaccine does not exceed 85%. In February 2006, a measles outbreak started by importation in the State Miranda; this extended to 7 states and lasted 50 weeks with an intermediate period of 17 weeks without reported cases. New cases were reported in the States Guarico and Amazon. The pattern of circulation of the silent period was determined through the use of retrospective search for measles; this showed that 57% of suspected cases did not enter the surveillance system. Molecular epidemiology made it possible to identify B3 as only genotype, which also circulated in Spain. The epidemiological and clinical characteristics of measles have been modified; these determine outbreaks identified late, of slow expansion, silent, and with limited case-fatality, compared with classical outbreaks. The outbreak spread by that behavior was not recognized and the classical control measures did not result. The beginning of a broader and intense vaccination was delayed, partly by weaknesses in the sensitivity of the system. It is crucial to recognize the new behavior of measles and the effectiveness of the classical control measures, and especially to establish criteria for interruption of the circulation to control an outbreak in this stage of elimination.     

Measles in bone marrow transplant recipients during an outbreak in S?o Paulo, Brazil.

In 1997, a measles outbreak was identified in S?o Paulo. Between February and December, 20 185 cases were confirmed. From April to July 1997, a seroepidemiologic survey was conducted to identify the recipients of bone marrow (BM) transplants who were susceptible to measles and the occurrence of measles in this population. A total of 156 patients were screened by enzyme immunoassay (EIA). Patients with IgG titers more than 100 mIU/mL were considered immune. Measles reimmunization records were also reviewed. Thirty-two vaccinated patients underwent serologic evaluation. Six of 22 patients (27.3%) within 3 years after vaccination lost measles immunity, in contrast to 7 of 10 patients (70%) vaccinated longer than 3 years previously (P =.049). Among the 122 nonvaccinated patients, 41 (33.6%) were susceptible to measles: 4 of 47 patients (8.5%) within the first year after BM transplantation (BMT), and 37 of the 75 patients (49.3%) after the first year after BMT (P <.001). Eight recipients acquired measles, confirmed by serology (EIA). High-avidity IgG antibodies were observed in the acute phase of measles, suggesting a secondary immune response. Measles interstitial pneumonia was observed in one patient. Seven patients had mild symptoms. Exanthema was present in all patients. All but one patient had fever and nonproductive cough. Koplik spots could be observed in 5 patients. Measles can be mild in BM transplant recipients. Exanthema is frequently present but not often typical. Immunity to measles decreases after day +365 after BMT. Additional studies are needed to evaluate the safety of measles vaccine after the first year of BMT, mostly during outbreaks.     

Measles outbreak in Sri Lanka, 1999-2000

A large measles outbreak occurred in Sri Lanka from October 1999 through June 2000 following a period of low incidence. During this period, >15,000 suspected cases were reported to the central Epidemiological Unit of the Department of Health Services. The outbreak was investigated through review of surveillance data for 1999-2000, which were compared with previous surveillance data. Among the clinically confirmed cases, the highest morbidity rate (114/100,000 population) was observed among children <9 months of age. Nearly 54% of the cases were among persons >/=15 years old, and this percentage had increased over the previous decade. Forty percent of cases had a history of measles vaccination. There were 5 deaths, giving a case-fatality rate of 0.1%. Action taken during the outbreak and plans for future outbreak prevention strategies were also evaluated.     

Interruption of measles transmission in Brazil, 2000-2001

In 1992, Brazil adopted the goal of measles elimination by the year 2000; however, in 1997, after a 4-year period of good control, there was a resurgence of measles in Brazil. In 1999, to achieve the elimination goal, Brazil implemented the Supplementary Emergency Measles Action plan, with one measles surveillance technician designated to each state. Of 10,007 suspected measles cases reported during 1999, 908 (9.1%) were confirmed, and of them 378 (42%) were confirmed by laboratory analysis. Of 8358 suspected measles cases reported in 2000, 36 (0.4%) were confirmed (30 [83%] by laboratory); 92% of the discarded cases were classified on the basis of laboratory testing. In 2001, only 1 of 5599 suspected measles cases was confirmed, and it was an imported case from Japan. The last outbreak occurred in February 2000, with 15 cases. Current data suggest interruption of indigenous measles transmission in Brazil.     

A high school measles outbreak--control measures and vaccine efficacy

Epidemiological investigation of a March 2007 detected measles outbreak of 28 cases in a 792-student high school in Tokyo. Students with a vaccination history had significantly milder symptoms than those without, and no cases occurred among students having two of measles vaccine in two doses of measles vaccine in their childhood. Vaccine efficacy (VE) calculated in our investigation was 93.9% (95% CI:87-97), and no significant difference was observed in vaccine type or manufacturer product. Students and parents were extremely difficult to persuade to cooperate in control measures such as emergency vaccination and home isolation through notification letters even during outbreaks. Schools should thus develop measles outbreak preparedness and response plans and identify potentially susceptible students in advance through documented proof of case histories and MCV vaccination. Outbreaks should promote early detection of patients and emergency vaccination targetting potentially susceptible students backed through close cooperation with medical facilities, education institutions, and the public health sector, together with school closures as appropriate.     

The elimination of indigenous measles transmission in England and Wales

Following a school-based measles-rubella vaccination campaign in November 1994, enhanced surveillance of measles, including IgM antibody testing of oral fluid from clinically diagnosed case-patients, was introduced in England and Wales. Between 1995 and 2001, 665 cases of measles were confirmed, including 371 (56%) confirmed only by IgM detection in oral fluid. Two hundred thirty-nine cases (36%) were sporadic and 426 (64%) were associated with 61 clusters. Fifty-four (23%) of the 239 sporadic cases and 26 (43%) of the 61 clusters were associated with a probable or possible importation of infection from overseas, and a wide variety of genotypes were identified in each calendar year. The effective reproduction number for measles over the period was estimated to be below 0.7. These data suggest that most measles in the UK is acquired following limited transmission from an imported infection, and they confirm that measles elimination has been achieved and sustained over this period.     

Progress toward measles and rubella elimination in Egypt

Measles and rubella were common infectious diseases in Egypt during the prevaccine era. Monovalent measles vaccine was introduced in 1977, and measles vaccination coverage increased from <50% to >90% from 1980 to 1999; however, measles outbreaks continued to occur at 2- to 4-year intervals during this period. After the introduction of a second routine dose of measles vaccine as a combined measles-mumps-rubella (MMR) vaccine in 1999 and the implementation of measles immunization campaigns targeting 6- to 16-year-old children during 2000-2003, reported measles cases dramatically decreased by 2003. In 2002, Egypt established a goal to eliminate measles and rubella and to prevent congenital rubella syndrome (CRS) by 2010. Large-scale rubella and measles outbreaks in 2005-2007, however, led to a revision of the plan of action to achieve the 2010 goals. A nation-wide measles-rubella immunization campaign, targeting children, adolescents, and young adults 2-20 years old, was conducted in 2 phases during 2008-2009 and achieved coverage >95%. With the decrease to record low levels of cases of measles and rubella in 2009 and 2010, Egypt should achieve measles and rubella elimination in the near future, but high coverage(>95%) with 2 doses of measles-rubella vaccine needs to be maintained, measles-rubella surveillance strengthened, and CRS surveillance developed.     

Alterations in epidemics and vaccination for measles during a 20 year period and a strategy for elimination in Kurashiki City, Japan

In Japan, an epidemic of measles occurs every few years. An estimated 100-200,000 people contract the disease each year and 50-100 patients die. Following the eradication of poliomyelitis, the World Health Organization made plans for global eradication of measles, and the Japanese Association of Pediatricians began advocating vaccination to eliminate measles in Japan by 2005. However, no big response has occurred nationwide. Therefore, we retrospectively look at changes in epidemics and measles vaccination during the past 20 years in Kurashiki City, Okayama Prefecture and developed a strategy for elimination through the results. The Japanese surveillance showed the numbers of measles patient in Okayama to be a few times higher than the mean number nationwide. The number of persons vaccinated was approximately 2,000-3,000 per year, while the number of births was about 6,000 per year. After passing a revised vaccination law in 1994, the number of vaccinations increased to more than 4,000, and the epidemic situation decreased to the nationwide level. However, the number of measles patients older than 15 years of age who were admitted to our hospital increased from 4% to 24% in the ratio to the whole. In the United States, school regulations require that children be vaccinated for MMR twice before admission to school, but the revised vaccination law in Japan was changed from a requirement to a recommendation. To eliminate measles, we should increase the vaccination rate for infants, and should vaccinate adolescents who have not been vaccinated or do not have a past history of measles. It is important to choose the subjects and then confirm their vaccination after the recommendation. We have developed a strategy that includes 1) advocacy for vaccination 2) selection for vaccination, 3) request for certification of vaccination, 4) convenience for vaccination. The goal after two years is for 1) a vaccination rate of more than 90% by end of one year of age, 2) a rate of vaccination and past history of measles in more than 90% of children before admission to kindergarten or public school.