Laboratory-confirmed Measles Cases Research Articles

Measles epidemic from 1951 to 2012 and vaccine effectiveness in Guangzhou, Southern China

Background Since the National Expanded Program on Immunization was implemented in China, considerable progress has been made in reducing the incidence of measles. However, the incidence of measles increased again in 2004. Few post-marketing studies on measles vaccine effectiveness were reported in China. In this study, we aimed to describe the measles epidemic and to evaluate the effectiveness of the measles vaccine in Guangzhou, southern China.Methods Based on the surveillance data for measles, we investigated the epidemiology during different periods between 1951 and 2012. We analyzed the clinical characteristics of laboratory-confirmed cases of measles between 2009 and 2012 and conducted a case-control study using test-negative cases as controls. We determined the protective effect of measles vaccine.Results The highest annual incidence in Guangzhou was 2187.15/100 000 in 1964, and the lowest was 0.32/100 000 in 2011. The average incidence of measles from 1951 to 2012 was 306.27/100 000. There was a significant tendency of decline in recent years. From 2009 to 2012, there are 700 laboratory-confirmed cases reported with an average onset age of 2.5 (median) years. The non-vaccinated target population (age <8 months and ≥15 years) accounted for 56.7% of the cases. The transient (non-resident) population accounted for 51.3% of the cases. Fewer cases were observed in the population targeted for measles vaccine (aged 8 months to 14 years). The effectiveness of a single dose of the measles vaccine was 89.1% (95% confidence interval (CI), 44.5–97.9), and the effectiveness of ≥2 doses of the measles vaccine was 97.8% (95% CI, 88.3–99.6) in children aged 8 months to 14 years old.Conclusions There is a significant overall decline in the incidence of measles (including clinical and laboratory confirmed cases) in the measles vaccine targeted population in Guangzhou. Two doses of measles vaccine are more effective than one dose in preventing measles in China. In order to accelerate the elimination of measles, vaccination should also be given to the transient and the non-vaccine targeted population.

The effect of measles on health-related quality of life: a population-based prospective study

BackgroundTo enable decisions about investment across different areas of health care, health needs to be measured in a standardised way. In the UK, the quality-adjusted life-year (QALY) is the preferred metric. However, no measure of the QALY loss associated with measles is available, either for the UK or elsewhere. This study aimed to estimate the quality of life effect of measles by surveying patients with measles in England. MethodsWe did a population-based prospective study using postal questionnaires to request information about people's illness along with an age-specific EQ-5D—a validated questionnaire commonly used to quantify QALYs. Public Health England reported 3207 laboratory-confirmed cases of measles in England between Jan 1, 2012, and June 30, 2013. Beginning in June, 2012, cases confirmed by IgM detection or PCR, or both, were sent postal questionnaires. Individuals with laboratory-confirmed measles reported in travellers communities were not invited to participate in the study. Public Health England engages with this community through different protocols and procedures. Public Health England has ethics approval to conduct enhanced outbreak surveillance. This approval includes the collection of health-related quality of life (HRQoL) data. Consent was implied through the return of a completed questionnaire to Public Health England. Findings507 questionnaires have been sent to individuals with confirmed measles; 203 have been returned (40·0%). The mean HRQoL loss per measles case was the equivalent of 6·9 days (95% CI 6·0–7·8), or 0·019 QALYs, after undertaking a missing value regression analysis. 37 (18·2%) of 203 responses were from parents or guardians of patients less than 1 year old. There was no evidence that patients who were hospitalised were more likely to respond to the questionnaire. 196 (96·6%) of 203 patients reported at least one complication, including fever (187 [92·1%]), conjunctivitis (114 [56·2%]), and difficulty breathing or coughing (162 [79·8%]). The mean duration of illness was 13·8 days (95% CI 12·5–15·1). 128 (63·1%) of 203 patients recorded absence from work or school, with a mean duration of 9·6 days (95% CI 8·3–11·0). 75 (39·6%) of 203 patients recorded that their primary caregivers were absent from work, with a mean duration of 7·3 days (95% CI 5·8–8·7). 74 patients (36·5%) reported spending at least one night in hospital, with a mean stay of 4·2 nights (95% CI 3·3–5·2). 193 patients (95·1%) reported contact with health-care services, with a mean of 4·0 contacts (95% CI 3·7–4·4). 71 (78·0%) of 91 patients reported severe problems due to measles infection on the EQ-5D dimension of health concerning their ability to undertake their usual activities. 24 (26·4%) of 91 patients reported severe problems in the depression or anxiety dimension. InterpretationThe HRQoL loss due to measles was greater than we had expected. With a mean duration of infection of 13·8 days, this finding can be interpreted as living with 50% health utility for almost 2 weeks. For context, the mean HRQoL loss for influenza is 0·008 QALYs or 2·92 days. The mean HRQoL loss due to varicella is 0·0027 QALYs or 0·99 days (<15 years old) and 0·0038 QALYs or 1·39 days (≥15 years old). The HRQoL results will inform cost-effectiveness analyses that test new or existing interventions for measles outbreaks. FundingThis work was funded by a Career Development Fellowship supported by the National Institute for Health Research (grant number NIHR-CDF-2011-04-019). The views expressed in this publication are those of the authors and not necessarily those of the NHS, the National Institute of Health Research, or the Department of Health.

Measles Outbreak in South Africa: Epidemiology of Laboratory-Confirmed Measles Cases and Assessment of Intervention, 2009–2011

BackgroundSince 1995, measles vaccination at nine and 18 months has been routine in South Africa; however, coverage seldom reached >95%. We describe the epidemiology of laboratory-confirmed measles case-patients and assess the impact of the nationwide mass vaccination campaign during the 2009 to 2011 measles outbreak in South Africa.MethodsSerum specimens collected from patients with suspected-measles were tested for measles-specific IgM antibodies using an enzyme-linked immunosorbent assay and genotypes of a subset were determined. To estimate the impact of the nationwide mass vaccination campaign, we compared incidence in the seven months pre- (1 September 2009–11 April 2010) and seven months post-vaccination campaign (24 May 2010–31 December 2010) periods in seven provinces of South Africa.ResultsA total of 18,431 laboratory-confirmed measles case-patients were reported from all nine provinces of South Africa (cumulative incidence 37 per 100,000 population). The highest cumulative incidence per 100,000 population was in children aged <1 year (603), distributed as follows: <6 months (302/100,000), 6 to 8 months (1083/100,000) and 9 to 11 months (724/100,000). Forty eight percent of case-patients were ≥5 years (cumulative incidence 54/100,000). Cumulative incidence decreased with increasing age to 2/100,000 in persons ≥40 years. A single strain of measles virus (genotype B3) circulated throughout the outbreak. Prior to the vaccination campaign, cumulative incidence in the targeted vs. non-targeted age group was 5.9-fold higher, decreasing to 1.7 fold following the campaign (P<0.001) and an estimated 1,380 laboratory-confirmed measles case-patients were prevented.ConclusionWe observed a reduction in measles incidence following the nationwide mass vaccination campaign even though it was conducted approximately one year after the outbreak started. A booster dose at school entry may be of value given the high incidence in persons >5 years.

Measles virus genotyping an important tool in measles outbreak investigation in Norway, 2011

This study describes 33 laboratory-confirmed cases of measles that occurred in Norway in 2011, mainly among unvaccinated children between seven months and 10 years of age. Laboratory testing included detection of anti-measles IgM- and IgG antibodies by enzyme-linked immunosorbent assay (ELISA) and molecular detection and characterisation of measles virus by polymerase chain reaction (PCR) and sequencing. Epidemiological data and genotyping revealed that the measles cases originated from eight separate importations, resulting in four outbreaks and four sporadic cases. Except for the first outbreak which affected 18 cases, limited secondary spread occurred in each of the three other outbreaks. The outbreaks were caused by measles virus genotypes B3, D4 and D9, whereas genotypes D8 and B3 were detected in the sporadic cases. This study highlights that genetic characterisation of measles virus is an essential tool in the laboratory surveillance of measles, especially in countries like Norway which are approaching the measles elimination goal. The investigation revealed that importation of measles resulted in subsequent transmission within Norway to non-vaccinated individuals, and twelve cases occurred in healthcare settings, involving both staff and children. The four cases detected among healthcare workers (HCWs) emphasised that the coverage of measles-mumps-rubella (MMR) vaccination among healthcare personnel needs to be improved and both primary and secondary vaccine failure was demonstrated in two fully immunised HCWs.

Successful Control and Impending Elimination of Measles in the Islamic Republic of Iran

Measles is still one of the most common infectious killers of children in the world, especially in developing countries. In Iran, during the prevaccine era, 150,000-500,000 cases of measles were reported annually, with a death rate of 10%-15%. After the establishment of Expanded Program on Immunization program in 1984, vaccination rates for the first and second doses of measles vaccine increased to >90% by the mid-1990s, and the number of measles cases decreased to 2652 in 1996. In response to increased numbers of cases in older age groups during 1996-2002, a nationwide measles-rubella vaccination campaign was conducted in 2003, and 33,100,000 persons (99%) aged 5-25 years were vaccinated. During 2004-2009, 221 laboratory-confirmed measles cases (<1 case per million population) were detected, primarily in rural areas and among migrant groups who traveled to or came from high-incidence countries. High routine immunization coverage, low disease incidence, and surveillance system data suggest that interruption of endemic virus transmission might have already been achieved in Iran, but challenges remain and continued efforts are needed to sustain this accomplishment.

Measles Outbreak among Unvaccinated Children in Bajura

Measles outbreak occurs when there are three or more laboratory confirmed measles cases in a village in a period of one month. Integrated surveillance system has helped to identify the measles outbreak, to characterize its epidemiology and to timely respond it. This is a descriptive study of measles outbreak that occurred in Bajura district in February to March 2010. The epidemiological characteristics of the outbreak are described. The outbreak was investigated from 4-8 March 2010 with necessary epidemiological information and biological specimen collection. One month follow up was done to determine the clinical outcome of the measles cases. A total of 36 people had measles; 97% of them were under 15 years of age and 89% had not been immunized with measles vaccine. Attack rate and vaccine efficacy was 23% and 50% amongst children less than 15 years of age and case fatality rate (CFR) was 3%. Biological samples were collected from 11 patients; all of which tested IgM positive for measles and genotype D8 was isolated. CFR of this outbreak is higher than the national CFR. Vaccine efficacy of 50% points towards the need for investigation of vaccine logistics and cold chain system. Moreover, this laboratory test confirmed an outbreak showing that the measles virus could be imported from an endemic region and rapidly spread through a susceptible population who were previously not immunized.

Molecular evolution of measles viruses circulated in Taiwan 1992-2008

Genetic analyses of viral samples from 74 laboratory confirmed measles cases occurring in Taiwan during 1992-2008 identified six viral genotypes D3, D5, D9, G2, H1 and H2. The most frequently detected genotype, H1, was associated with outbreaks in 1994 and 2002, and was the likely indigenous genotype in 1992. In response to the outbreaks, two catch-up campaigns were launched and a routine second dose of measles, mumps, and rubella vaccine at entry to elementary school was introduced. The vaccination campaigns successfully reduced the number of measles cases in Taiwan, and many of the more recent cases can be traced to importations, primarily from other Asian countries. A number of measles genotypes which were associated with outbreaks in other Asian countries were detected among the more recent cases. The more recent genotype H1 viruses had sequences that were identical to those currently circulating in China or associated with international importation of virus.

Measles outbreak in South Africa, 2003-2005.

Measles was virtually eliminated in South Africa following control activities in 1996/7. However, from July 2003 to November 2005, 1676 laboratory-confirmed measles cases were reported in South Africa. We investigated the outbreak's cause and the role of HIV. We traced laboratory-confirmed case-patients residing in the Johannesburg metropolitan (JBM) and O. R. Tambo districts. We interviewed laboratory--or epidemiologically confirmed case-patients or their caregivers to determine vaccination status and, in JBM, HIV status. We calculated vaccine effectiveness using the screening method. Household survey in JBM and O. R. Tambo districts. Outcome measures. Vaccine effectiveness, case-fatality rate, and hospitalisations. In JBM, 109 case-patients were investigated. Of the 57 case-patients eligible for immunisation, 27 (47.4%) were vaccinated. Fourteen (12.8%) case-patients were HIV infected, 46 (42.2%) were HIV uninfected, and 49 (45.0%) had unknown HIV status. Among children aged 12-59 months, vaccine effectiveness was 85% (95% confidence interval (CI): 63, 94) for all children, 63% for HIV infected, 75% for HIV uninfected, and 96% for children with unknown HIV status. (Confidence intervals were not calculated for sub-groups owing to small sample size.) In O. R. Tambo district, 157 case-patients were investigated. Among the 138 case-patients eligible for immunisation, 41 (29.7%) were vaccinated. Vaccine effectiveness was 89% (95% CI 77, 95). The outbreak's primary cause was failure to vaccinate enough of the population to prevent endemic measles transmission. Although vaccine effectiveness might have been lower in HIV-infected than in uninfected children, population vaccine effectiveness remained high.

Residual susceptibility to measles among young adults in Victoria, Australia following a national targeted measles-mumps-rubella vaccination campaign

BackgroundPast measles immunisation policies in Australia have resulted in a cohort of young adults who have been inadequately vaccinated, but who also have low levels of naturally acquired immunity because immunisation programs have decreased the circulation of wild virus. A measles-mumps-rubella (MMR) immunisation campaign aimed at addressing this susceptibility to measles among young adults was conducted in Australia in 2001–2. By estimating age-specific immunity, we aimed to evaluate the success of this campaign in the state of Victoria.MethodsWe conducted serosurveys after the young adult MMR program at state and national levels to estimate immunity among young adults born between 1968–82. We compared results of the Victorian (state) surveys with the Victorian component of the national surveys and compared both surveys with surveys conducted before the campaign. We also reviewed all laboratory confirmed measles cases in Victoria between 2000–4.ResultsThe Victorian state serosurveys indicated no significant change in immunity of the cohort following the young adult MMR campaign (83.9% immune pre and 85.5% immune post campaign) while the Victorian component of the national serosurvey indicated a significant decline in immunity (91.0% to 84.2%; p = 0.006). Both surveys indicated about 15% susceptibility to measles among young Victorian adults after the campaign. Measles outbreaks in Victoria between 2000–4 confirmed the susceptibility of young adults. Outbreaks involved a median of 2.5 cases with a median age of 24.5 years.ConclusionIn Victoria, the young adult MMR program appears to have had no effect on residual susceptibility to measles among the 1968–82 birth cohort. Young adults in Victoria, as in other countries where past immunisation policies have left a residual susceptible cohort, represent a potential problem for the maintenance of measles elimination.

Measles virus protein-specific IgM, IgA, and IgG subclass responses during the acute and convalescent phase of infection.

The availability of new generation serological assays allowed re-evaluation of the antibody response to measles virus. IgM, IgA, total IgG, and IgG subclass responses were studied to the three major immunogenic measles virus proteins: the fusion protein (F), haemagglutinin (H), and nucleoprotein (N). Plasma samples were obtained from clinically diagnosed measles cases (n = 146) in Khartoum (Sudan) within a week after onset of the rash. Convalescent phase samples were collected from 32 of 117 laboratory-confirmed measles cases at different time points after onset of rash. Glycoprotein-specific IgM, IgG, and IgA antibody levels correlated well to the N-specific response. For IgG and IgA, responses to F were higher than to H. IgA antibody levels were undetectable in about one third of the laboratory-confirmed cases during the acute phase, but positive in all patients tested 1-4 weeks after infection. IgM levels declined rapidly and were lost 3-6 months after infection. IgA levels declined slowly during the first year but did not return to background levels during the subsequent 2 years. IgG avidity maturation was detected during a 3-6 month period after infection. The predominant IgG subclasses during the acute phase were IgG(1) and IgG(3). The latter was lost in the convalescent phase, while the IgG(4) isotype showed a slight rise afterwards. Interestingly, acute phase IgG(3) and IgA responses were associated, and were only detected in samples with high IgG. This study provides a comprehensive perspective on the antibody response to wild-type measles virus infection.

Progress toward interruption of endemic measles transmission in Tunisia.

Measles was the second leading cause of infant mortality in Tunisia prior to introduction of measles vaccination in 1979. The number of reported measles cases has decreased from 3007 in 1981 to 47 cases in 2000 due in part to the high coverage rates achieved after 1992. During 1998, a measles catch-up campaign vaccinated 1,846,657 children (95%) aged 6-16 years, and a follow-up campaign for children aged 9 months to 5 years in 2001 reached 547,766 (94%). During 1999-2001, 1717 cases of rash and fever illness were tested for measles; only 3 (0.2%) were positive for measles. From February to July 2002, an outbreak of measles involving 87 cases occurred in Tunisia in a health care setting and 56 (64%) patients were aged 15-30 years. The low number of laboratory-confirmed measles cases during 1999-2001 suggests endemic measles transmission may have been interrupted.

First 5 years of measles elimination in southern Africa: 1996–2000

Measles is the leading cause of vaccine-preventable death in Africa. Regional measles elimination is considered feasible using current vaccines and a series of WHO-recommended strategies. We aimed to interrupt transmission of measles, and to use case-based surveillance to show the effect of such interruption. In southern Africa from 1996, seven countries with a total population of approximately 70 million and with relatively high routine vaccination coverage implemented measles elimination strategies. In addition to routine measles immunisation at 9 months of age, these included nationwide catch-up campaigns among children aged 9 months to 14 years, then follow-up campaigns every 3-4 years among children aged 9-59 months, and the establishment of case-based measles surveillance with serological diagnostic confirmation. Nearly 24 million children aged 9 months to 14 years were vaccinated, with overall vaccination coverage of 91%. Reported clinical measles cases declined from 60000 in 1996 to 117 laboratory-confirmed measles cases in 2000. Reported measles deaths declined from 166 in 1996 to zero in 2000. No increase in adverse events was noted after the measles vaccination campaign. A reduction in measles mortality and morbidity can be achieved in very low-income countries, in countries that split their vaccination campaigns by geographical area or by age-group of the target population, and where initial routine measles vaccination coverage among infants was <90%, even when prevalence of HIV/AIDS was extremely high. Continued high-level national commitment will be crucial to implementation and maintenance of proven strategies in southern Africa.