Measles Case-based Surveillance System Research Articles

Trends of measles in Tanzania: A 5-year review of case-based surveillance data, 2018-2022

ObjectivesTanzania observed a gradual increase in the number of measles cases since 2019 with a large outbreak recorded during 2022. This study describes the trend of measles in Tanzania over a 5-year period from 2018-2022. MethodsThis was a descriptive study conducted using routine measles case-based surveillance system including 195 councils of the United Republic of Tanzania. ResultsBetween 2018 and 2022 there were 12,253 measles cases reported. Out of 10,691 (87.25%) samples tested by enzyme-linked immunosorbent assay, 903 (8.4%) were measles immunoglobulin M positive. The highest number of laboratory-confirmed measles cases was in 2022 (64.8%), followed by 2020 (13.8%), and 2019 (13.5%). Out of 1279 unvaccinated cases, 213 (16.7%) were laboratory-confirmed measles cases compared to 77/723 (10.6%) who were partially vaccinated and 71/1121 (6.3%) who were fully vaccinated (P < 0.001). Children aged between 1-4 years constituted the most confirmed measles cases after laboratory testing, followed by those aged 5-9 years. There was a notable increase in the number of laboratory-confirmed measles cases in children <1 year and 10-14 years during 2022 compared to previous years. The vaccination coverage of the first dose of measles-containing vaccine (MCV1) was maintained >90% since 2013 while MCV2 increased gradually reaching 88% in 2022. ConclusionsAccumulation of susceptible children to measles due to suboptimal measles vaccination coverage over the years has resulted in an increase in the number of laboratory-confirmed measles cases in Tanzania with more cases recorded during the COVID-19 pandemic. Strengthening surveillance, routine immunization, and targeted strategies are key to achieving the immunity levels required to interrupt measles outbreaks.

Evaluation of the measles case-based surveillance system in Kwekwe city, 2017-2020: a descriptive cross-sectional study.

Introductionin 2011, WHO African region set a target for elimination of measles by 2020. During period 2017-2020, Kwekwe city, with an estimated population of 117,116, detected one case of suspected measles. This was against a target of 2 cases per year. We evaluated the system to establish why it was failing to detect at least 2 cases per year.Methodswe conducted a descriptive cross-sectional study using the Centre for Disease Control (CDC) Updated Guidelines. Nineteen health facilities were selected and fifty-seven health workers were randomly recruited. An interviewer-administered questionnaire and checklists were used to collect data. We generated frequencies, proportions, and means.Resultsthe mean years in service was 22.8 years (SD=12.6). Thirty (52.6%) respondents had fair knowledge. Fourteen (73.7%) of the nineteen respondents who had ever completed case investigation forms took between 10-20 minutes to complete. Only two (10.5%) of the nineteen facilities had case investigation forms. The majority of the respondents 54 (93%) were willing to continue participating in the measles Community Base Surveillance System (CBSS). None of the health facilities had used the system to inform decision-making. Reasons highlighted for poor suspected measles case detection included lack of health worker training 28/57 (49.1%).Conclusiondespite the high age in service, knowledge of the surveillance system was mostly fair. The system was found to be simple, not stable and not useful. The main reason for the system failure was lack of health worker training. We recommend retraining on Integrated Disease Surveillance and Response (IDSR) and case investigation forms distribution.

Trends in measles incidence and measles vaccination coverage in Nigeria, 2008–2018

IntroductionAll WHO regions have set measles elimination objective for 2020. To address the specific needs of achieving measles elimination, Nigeria is using a strategy focusing on improving vaccination coverage with the first routine dose of (monovalent) measles (MCV1) at 9 months, providing measles vaccine through supplemental immunization activities (children 9–59 months), and intensified measles case-based surveillance system. MethodsWe reviewed measles immunization coverage from population-based surveys conducted in 2010, 2013 and 2017–18. Additionally, we analyzed measles case-based surveillance reports from 2008–2018 to determine annual, regional and age-specific incidence rates. FindingsSurvey results indicated low MCV1 coverage (54.0% in 2018); with lower coverage in the North (mean 45.5%). Of the 153,097 confirmed cases reported over the studied period, 85.5% (130,871) were from the North. Moreover, 70.8% (108,310) of the confirmed cases were unvaccinated. Annual measles incidence varied from a high of 320.39 per 1,000,000 population in 2013 to a low of 9.80 per 1,000,000 in 2009. The incidence rate is higher among the 9–11 months (524.0 per million) and 12–59 months (376.0 per million). Between 2008 and 2018, the incidence rate had showed geographical variation, with higher incidence in the North (70.6 per million) compare to the South (17.8 per million). ConclusionThe aim of this study was to provide a descriptive analysis of measles vaccine coverage and incidence in Nigeria from 2008 to 2018 to assess country progress towards measles elimination. Although the total numbers of confirmed measles cases had decreased over the time period, measles routine coverage remains sub-optimal, and the incidence rates are critically high. The high burden of measles in the North highlight the need for region-specific interventions. The measles program relies heavily on polio resources. As the polio program winds down, strong commitments will be required to achieve elimination goals.

The Epidemiology of Rubella in Lesotho before the Introduction of a Rubella Containing Vaccine: A Review of Measles Case-based Surveillance, 2012-2016

Aim: The aim of the study was to determine the burden and epidemiology of rubella infection in Lesotho before the introduction of a rubella-containing vaccine. It was also to assess the performance of the measles case-based surveillance system in Lesotho.&#x0D; Study Design: Retrospective cross-sectional descriptive study.&#x0D; Place and Duration of Study: The study was done in Lesotho from February to March 2019 based on the 2012 to 2016 data.&#x0D; Methods: There was a review of the measles case-based surveillance data with a total of 1587 suspected cases reported during the study period. Samples were collected from suspected measles cases and tested for measles. Those samples that tested negative for measles were subsequently tested for rubella IgM at the National Reference Laboratory. The serum samples were analysed for rubella IgM using commercial enzyme-linked immunosorbent assay (ELISA) kits SERION and EUROIMMUN.&#x0D; Results: There were 2 measles IgM and 748 rubella IgM positive cases confirmed. The rubella IgM positive cases accounted for 48% of the samples tested for rubella infection. There were also several rubella outbreaks during the study period. The Lesotho surveillance system met the two principal surveillance performance indicators for each year during the period of the study.&#x0D; Conclusion: This study showed that there was high level of rubella sero-positivity with several outbreaks of rubella infections during the study period. Rubella infection was predominantly seen in those aged between 5 and &lt;13 years of age. This justified the introduction of a rubella containing vaccine in Lesotho in 2017. Although the two principal surveillance performance indicators (non-measles febrile rash illness rates and the percentage of districts that reported at least one case of measles with blood specimen per year) were met during the period under review, there were districts that performed poorly. This study revealed the need for strengthening of rubella-containing vaccine component of routine immunization to lower the impact of rubella infection in Lesotho. A detailed district level review to identify and address the causes of poor performance in some districts is recommended. There is also a need to identify the current challenges and evaluate the impact of the recently introduced rubella-containing vaccine on rubella infection in Lesotho.

An 11-year trend of rubella incidence cases reported in the measles case-based surveillance system, Ghana

Introductionrubella is vaccine-preventable and vaccination is the most cost-effective approach to control the disease and avoid the management of congenital rubella syndrome cases. Ghana introduced the rubella vaccine into the routine immunization program in 2013. Since then there have not been any evaluation of the epidemiology of rubella. We determined the disease trends and the population demographics of rubella cases, in the Ghana national measles case-based surveillance system.Methodswe reviewed the measles case-based surveillance data from 2007 to 2017. Descriptive data statistics was done and expressed as frequencies and proportions. Chi-square test was used to establish associations.Resultsa total of 11,483 suspected cases for measles received and tested for measles IgM antibodies and 1,137(12.98%) confirmed positive for the period. Of these 10,077 were negative and 250 indeterminate for measles and tested for rubella and 2,090 (20.23%) confirmed positive for rubella IgM antibodies. More females (21.45%) were affected than males (19.48%). Majority of the confirmed positives were recorded in the urban areas. Children aged 15 years or less were mostly affected. There was a statistical difference between incidence cases and sex (χ2=6.03, p-value = 0.014), or age (χ2=283.56, p-value < 0.001) or area (χ2= 6.17, p-value = 0.013). Most infections occurred during the dry season.Conclusionchildren less than 15 years were mostly affected with majority being females. The highest incidence of cases was before the rains and occurred mostly in urban areas. The incidence of cases has declined significantly with the introduction of the rubella vaccine.

Review of measles cases, surveillance indicators and predictors from case-based laboratory data over five years (2014–2018) in Bayelsa State, Nigeria

Background: Measles is a vaccine preventable, highly transmissible viral infection that affects mostly children under five years. It has been ear marked for eradication and Nigeria adopted the measles elimination strategies of the World Health Organization (WHO) African region to reduce cases and deaths. This study was done to determine trends in measles cases in Bayelsa state, to describe cases in terms of person and place, identify gaps in the case-based surveillance data collection system and identify risk factors for measles infection. Methods and materials: We carried out a secondary data analysis of measles case-based surveillance data for the period of January 2014 to December 2018 obtained in Microsoft Excel from the State Ministry of Health. Cases were defined according the World Health Organization (WHO) standard case definitions. We calculated frequencies, proportions, estimated odds ratios (OR), 95% confidence intervals (CI) and multivariate analysis. Results: A total of 449 cases of measles were reported. There were 245 (54.6%) males and the most affected age group was 1–4 years with 288 (64.1%) cases. Of all cases, 289 (9.35%) were confirmed and 70 (48.27%) had received at least one dose of measles vaccine. There was an all year transmission with increased cases in the 4th quarter of the year. Yenegoa local government area had the highest number of cases. Timeliness of specimen reaching the laboratory and the proportion of specimens received at the laboratory with results sent to the national level timely was below WHO recommended 80% respectively. Predictors of measles infection were, age less than 5 years (AOR: 0.57, 95% CI: 0.36–0.91) and residing in an urban area (AOR: 1.55, 95% CI: 1.02–2.34). Conclusion: Measles infection occurred all year round, with children less than 5 years being more affected. Measles case-based surveillance system showed high levels of case investigation with poor data quality and poor but improving indicators. Being less than 5 years was protective of measles while living in urban areas increased risk for infection. We recommended to the federal government to prioritize immunization activities in the urban centers, start campaigns by the 4th quarter and strengthen regional laboratory capacities while the State government to continue to support measles surveillance activities.

Trends in measles cases in Bayelsa state, Nigeria: a five-year review of case-based surveillance data (2014\u20132018)

BackgroundMeasles is a vaccine preventable, highly transmissible viral infection that affects mostly children under five years. It has been ear marked for elimination and Nigeria adopted the measles elimination strategies of the World Health Organization (WHO) African region to reduce cases and deaths. This study was done to determine trends in measles cases in Bayelsa state, to describe cases in terms of person and place, identify gaps in the case-based surveillance data collection system and identify risk factors for measles infection.MethodsWe carried out a secondary data analysis of measles case-based surveillance data for the period of January 2014 to December 2018 obtained in Microsoft Excel from the State Ministry of Health. Cases were defined according to WHO standard case definitions. We calculated frequencies, proportions, estimated odds ratios (OR), 95% confidence intervals (CI) and multivariate analysis.ResultsA total of 449 cases of measles were reported. There were 245(54.6%) males and the most affected age group was 1–4 years with 288(64.1%) cases. Of all cases, 289(9.35%) were confirmed and 70 (48.27%) had received at least one dose of measles vaccine. There was an all-year transmission with increased cases in the 4th quarter of the year. Yenegoa local government area had the highest number of cases. Timeliness of specimen reaching the laboratory and the proportion of specimens received at the laboratory with results sent to the national level timely were below WHO recommended 80% respectively. Predictors of measles infection were, age less than 5 years (AOR: 0.57, 95% CI: 0.36–0.91) and residing in an urban area (AOR: 1.55, 95% CI:1.02–2.34).ConclusionsMeasles infection occurred all-year round, with children less than 5 years being more affected. Measles case-based surveillance system showed high levels of case investigation with poor data quality and poor but improving indicators. Being less than 5 years was protective of measles while living in urban areas increased risk for infection. We recommended to the state government to prioritize immunization activities in the urban centers, start campaigns by the 4th quarter and continue to support measles surveillance activities and the federal government to strengthen regional laboratory capacities.

Performance of Measles Case-based Surveillance System in Rivers State, Nigeria 2011-2018

Performance of Measles Case-based Surveillance System in Rivers State, Nigeria 2011-2018

Sensitivity and positive predictive value of the measles surveillance system in Uganda, 2012-2015

Introduction : disease surveillance is a critical component in the control and elimination of vaccine preventable diseases. The Uganda National Expanded Program on Immunization strives to have a sensitive surveillance system within the Integrated Disease Surveillance and Response (IDSR) framework. We analyzed measles surveillance data to determine the effectiveness of the measles case-based surveillance system and estimate its positive predictive value in order to inform policy and practice. Methods : an IDSR alert was defined as 1 suspected measles case reported by a district in a week, through the electronic Health Management Information System. We defined an alert in the measles case-based surveillance system (CBS) as 1 suspected measles case with a blood sample collected for confirmation during the corresponding week in a particular district. Effectiveness of CBS was defined as having 80% of IDSR alerts with a blood sample collected for laboratory confirmation. Positive predictive value was defined as the proportion of measles case-patients who also had a positive measles serological result (IgM +). We reviewed case-based surveillance data with laboratory confirmation and measles surveillance data from the electronic Health Management Information System from 2012-2015. Results : a total of 6,974 suspected measles case-persons were investigated by the measles case-based surveillance between 2012 and 2015. Of these, 943 (14%) were measles specific IgM positive. The median age of measles case-persons between 2013 and 2015 was 4.0 years. Between 2013 and 2015, 72% of the IDSR alerts reported in the electronic Health Management Information System, had blood samples collected for laboratory confirmation. This was however less than the WHO recommended standard of 80%. The PPV of CBS between 2013 and 2015 was 8.6%. Conclusion : effectiveness of measles case-based surveillance was sub-optimal, while the PPV showed that true measles cases have significantly reduced in Uganda. We recommended strengthening of case-based surveillance to ensure that all suspected measles cases have blood samples collected for laboratory confirmation to improve detection and ensure elimination by 2020.

Evaluation of measles case-based surveillance system in Edo State, Nigeria, 2016

Introduction : measles is one of the leading causes of death in children despite availability of effective and accessible measles vaccine. In 2015, over 134,200 deaths were recorded globally. Measles infection is endemic in Nigeria with outbreaks recorded all year round. In Nigeria, measles surveillance is active and it involves case reporting and feedback. The objectives of measles surveillance include predicting outbreaks by identifying geographic locations and age groups at risk and evaluating vaccination strategies. We described the surveillance system, assessed the system attributes and performance indicators.

Evaluation of measles case-based surveillance system in Edo State, Nigeria, January to December, 2016

Introduction: measles is one of the leading causes of death in children despite availability of effective and accessible measles vaccine. In 2015, over 134,200 deaths were recorded globally. Measles infection is endemic in Nigeria with outbreaks recorded all year round. In Nigeria, measles surveillance is active and it involves case reporting and feedback. The objectives of measles surveillance include predicting outbreaks by identifying geographic locations and age groups at risk and evaluating vaccination strategies. We described the surveillance system, assessed the system attributes and performance indicators.

Positive predictive value and effectiveness of measles case-based surveillance in Uganda, 2012-2015.

IntroductionDisease surveillance is a critical component in the control and elimination of vaccine preventable diseases. The Uganda National Expanded Program on Immunization strives to have a sensitive surveillance system within the Integrated Disease Surveillance and Response (IDSR) framework. We analyzed measles surveillance data to determine the effectiveness of the measles case-based surveillance system and estimate its positive predictive value in order to inform policy and practice.MethodsAn IDSR alert was defined as ≥1 suspected measles case reported by a district in a week, through the electronic Health Management Information System. We defined an alert in the measles case-based surveillance system (CBS) as ≥1 suspected measles case with a blood sample collected for confirmation during the corresponding week in a particular district. Effectiveness of CBS was defined as having ≥80% of IDSR alerts with a blood sample collected for laboratory confirmation. Positive predictive value was defined as the proportion of measles case-patients who also had a positive measles serological result (IgM +). We reviewed case-based surveillance data with laboratory confirmation and measles surveillance data from the electronic Health Management Information System from 2012–2015.ResultsA total of 6,974 suspected measles case-persons were investigated by the measles case-based surveillance between 2012 and 2015. Of these, 943 (14%) were measles specific IgM positive. The median age of measles case-persons between 2013 and 2015 was 4.0 years. Between 2013 and 2015, 72% of the IDSR alerts reported in the electronic Health Management Information System, had blood samples collected for laboratory confirmation. This was however less than the WHO recommended standard of ≥80%. The PPV of CBS between 2013 and 2015 was 8.6%.ConclusionIn conclusion, the effectiveness of measles case-based surveillance was sub-optimal, while the PPV showed that true measles cases have significantly reduced in Uganda. We recommended strengthening of case-based surveillance to ensure that all suspected measles cases have blood samples collected for laboratory confirmation to improve detection and ensure elimination by 2020.

Epidemiology of rubella virus cases in the pre-vaccination era of Ethiopia, 2009-2015.

BackgroundRubella is a common mild rash illness caused by rubella virus. The majority of infections occur in children and young adults. The infection is the cause of a serious birth defect known as Congenital Rubella Syndrome (CRS) when a woman acquires infection early in pregnancy. Ethiopia has not yet established rubella virus surveillance and has not yet introduced rubella vaccine into the routine immunization program. We characterize the epidemiology of laboratory confirmed rubella virus cases collected through measles surveillance from 2009 to 2015 to better understand the burden of the disease in the country.MethodsA descriptive analysis was made to characterize rubella cases reported through the national measles case based surveillance system. The measles case definition was used to capture potential rubella cases. A suspected measles case was a person with generalized rash and fever with cough, or coryza or conjunctivitis. Those cases whose sera were negative for measles IgM antibodies were tested for rubella IgM antibody. A confirmed rubella case was a person who tested positive for rubella IgM. Only laboratory confirmed rubella cases were analyzed in this article.ResultsBetween 2009 and 2015, a total of 28,284 serum/plasma samples were collected and tested for measles IgM antibody and 11,151 (39.4%) were found positive. A total of 17,066 measles IgM negative or indeterminate samples were tested for rubella virus IgM and 2615 (15.3%) were found positive during the same period. Of 2615 confirmed rubella cases, 52.2% were females. The age of confirmed cases ranged from one month to 42 years with a mean age of 7.3 years. Three-fourth of all confirmed rubella cases were aged less than 10 years. The number of laboratory confirmed rubella cases linearly increased from 83 in 2009 to 856 in 2013 but dropped to 222 and 319 in 2014 and 2015 respectively. Higher number of cases occurred in the hot dry season (January through June) and in the central and western part of Ethiopia with 127 lab-confirmed outbreaks in the study period.ConclusionsBased on our analysis, rubella was found to be endemic throughout Ethiopia. Children below the age of 10 years were the most affected. The burden of rubella cases varied from year to year but had a seasonal peak in March. To better understand the magnitude of rubella prior to vaccine introduction, establishing rubella surveillance system, conducting sero-prevalence studies among child bearing age females and establishing CRS sentinel surveillance among young infants are critical.

Epidemiology of rubella disease in south-west nigeria: trends and projection from measles case-based surveillance data

Although surveillance for rubella does not exist in Nigeria, a measles case-based surveillance system was introduced in 2005 as one of the strategies for measles morbidity control, and included laboratory testing for confirmation of the disease. In this report, we provide the epidemiological distribution of rubella-confirmed cases reported from the south-west zone of the country, and predict the expected number of cases in the ensuing years. A descriptive analysis was carried out of rubella cases reported in the measles case-based surveillance data from the south-west zone of Nigeria for the period 2007-2012. Using an additive time series model, we predicted the expected number of cases until the year 2015. Four hundred and thirty-eight (5.4%) rubella cases were confirmed from 8 046 suspected measles cases. Cases were confirmed from all six states within the zone. The majority (87.3%) were individuals < 15 years of age and 40.9% were female. Seasonal variation existed, with peaks of infection in the first and third triannual periods of the year, while annual trends showed peaks in 2007 and 2010. Based on projections, there was a reduction in the number of expected cases. Rubella testing, in parallel with measles case-based surveillance, provides understanding of the epidemiology of rubella infection in south-west Nigeria.

Measles outbreak in Northern Central African Republic 3 years after the last national immunization campaign.

BackgroundDespite huge efforts to promote widespread vaccination, measles remains an important cause of morbidity and mortality worldwide, especially in African children. In March 2011, an abnormally high number of cases were reported from the Ouham Prefecture, Central African Republic to the national measles case-based surveillance system. In response, reactive vaccination activities were implemented. The aims of this study were to investigate this outbreak and describe the response.MethodsMeasles cases were defined according to WHO recommendations. In the first weeks of the outbreak, blood samples were collected and sent to the Institut Pasteur in Bangui for laboratory confirmation by detection of IgM antibodies against measles virus. In addition, a portion of viral RNA was amplified from 5 IgM positive patient samples and the amplicons were sequenced for phylogenetic analysis.ResultsBetween March and September 2011, 723 clinical cases originated from the Ouham Prefecture, including 2 deaths, were reported. Amongst 59 blood samples collected, 49 were positive for the detection of IgM. A high number of self-declared vaccinated subjects (31%) were found amongst the cases. Most of the cases were under 5 years. The causative virus was found to belong to genotype B3.1. In response, 2 sub-national supplementary immunization activities were quickly conducted and limited this outbreak to mainly 2 sub-prefectures.ConclusionsThis outbreak was the largest epidemic of measles in CAR since 2002. Its occurrence, 3 years after the last national immunization campaign, highlights the necessity to pursue efforts and improve and extend immunization programs in order to reach measles elimination goal in Africa.

Trends in Performance of the National Measles Case-Based Surveillance System, Ministry of Health and Child Welfare, Zimbabwe (1999 - 2008)

Trends in Performance of the National Measles Case-Based Surveillance System, Ministry of Health and Child Welfare, Zimbabwe (1999 - 2008)

The Epidemiology of Rubella Disease in Ethiopia: Data From the Measles Case-Based Surveillance System

Rubella is usually a mild rash illness. However, when a woman contracts rubella early in pregnancy, serious consequences may occur, including birth defects known as congenital rubella syndrome (CRS). Information is limited on the epidemiology of rubella and CRS in Ethiopia. Rubella cases reported through the measles case-based surveillance system during 2004-2009 were analyzed. A total of 8212 samples were tested for rubella immunoglobulin (Ig) M, and 992 (12.1%) of these specimens had test results that were positive for rubella IgM. The age distribution of patients with rubella-positive cases ranged from 3 months to 44 years. The majority (94.7%) of the cases were in individuals <15 years of age. The proportion of positive specimens from urban areas (19.4%) was higher than that from rural areas (11.6%). Rubella is endemic in Ethiopia and mainly occurs among children and young adolescents. To better understand the burden of rubella and CRS, and to develop a national strategy for rubella control in Ethiopia, CRS surveillance will need to be established, and appropriate studies need to be conducted.

Preplanned National Measles Vaccination Campaign at the Beginning of a Measles Outbreak—Sierra Leone, 2009–2010

Large-scale measles outbreaks occurred throughout Africa from 2008-2010. In Sierra Leone, in November 2009, preceding a measles supplemental immunization activity (SIA), the largest measles outbreak in a decade started. We analyzed data from the national measles case-based surveillance system, developed a susceptibility profile of the population, and calculated vaccine effectiveness (VE) among children 12-59 months of age. From November 1, 2009 to July 13, 2010, 1,094 confirmed cases, including 9 deaths, were reported; 716 (66%) were <5 years of age. B3 genotype was identified. Measles attack rates per 100,000 population were highest among infants aged 6-8 months (56.4) and in Bo district (49.4). Districts with higher estimated SIA coverage tended to have lower attack rates (Spearman Correlation Coefficient=-0.63), p=0.07. Among 473 cases with information on vaccination status, 222 (47%) were unvaccinated; estimated VE was 74%. The 2009 measles SIA led to 165,000 fewer estimated susceptible individuals. The 2009 measles SIA reduced the overall magnitude of the outbreak, though routine and SIA coverage was insufficient to prevent it entirely. Maintaining high coverage through routine services and SIAs in all districts and conducting follow-up SIAs prior to the end of the low transmission season may prevent future outbreaks.