Measles in the Modern Era: A Review.

Measles is a viral illness considered eliminated in the United States; however, outbreaks still occur even in this modern era where vaccines are readily available for every child under government-sponsored financing programs. The most recent measles outbreak was reported in March 2024 in Chicago, Illinois. Many of these patients were children younger than age 5 years with unvaccinated or unknown vaccine status, and this outbreak was associated with a migrant shelter. Measles bears a resemblance to other exanthemic diseases of childhood. In populations where there is high vaccine coverage, measles is less likely to be in the differential diagnosis for most physicians; however, cases of vaccine failure have been described, and populations have risk factors for developing complications associated with measles. Therefore, this quick review aims to describe an illustrative case, followed by epidemiology, clinical manifestations, complications, diagnosis, and vaccines associated with measles. By the end of this article, clinicians should be able to recognize a potential measles case, select the most appropriate test to confirm the diagnosis, and thus, prevent the spreading of this highly contagious disease. [Pediatr Ann. 2024;53(9):e345-e350.].

Epidemiology of measles outbreaks, incidence and associated risk factors in Ethiopia from 2000 to 2023: a systematic review and meta-analysis.

BACKGROUND: Although a universal vaccine is available and Ethiopia is working outstandingly towards measles elimination, a recurrent measles outbreak has occurred each year in different parts of the country. Therefore, understanding the epidemiology of measles cases, the incidence of confirmed measles virus cases and related risk factors is crucial. Here, we conducted a systematic review and meta-analysis to summarize information regarding the epidemiology, measles incidence rate and risk factors for national measles infections occurring in the past two decades, from 2000 to 2023. METHODS: Data from electronic databases, including PubMed, African Journal Online, WHO databases and Google Scholars, were searched to identify studies describing measles outbreaks, incidence rates and associated factors in Ethiopia that occurred between 2000 and 2023. Important basic information was extracted in an Excel spreadsheet and imported into Comprehensive Meta-analysis Software version 3 to evaluate the associations between measles outbreaks and different risk factors. We pooled the odds ratios (ORs) and 95% confidence intervals (CIs) for every included risk factor to evaluate the associations with measles outbreaks. RESULTS: We included 36 studies involving 132,502 patients with confirmed measles cases in Ethiopia. The results of this systematic review and meta-analysis revealed that measles outbreaks were more frequently reported in the Oromia region (73,310 (33.1%)), followed by the Southern Nation Nationalities of Ethiopia region (29,057 (13.4%)). The overall pooled analysis indicated that the prevalence of measles susceptibility was 67.5% (95% CI: 67.3-67.8%), with an I2 of 99.86% and a p value for heterogeneity < 0.0001. The non-vaccinated status of the children, their contact history with measles cases, their travel history, the presence of cases in family or neighbors, and malnourished patients were identified as factors associated with the high prevalence and recurrent measles infections in Ethiopia. CONCLUSION: The results of this systematic review and meta-analysis indicated that the pooled prevalence of measles infection was high, which is a public health concern in Ethiopia. Thus, strengthening healthcare services, regular vaccination campaigns, and the integration of health education activities with other services may decrease the incidence rate.

Hospital-acquired infections and unvaccinated children due to chronic diseases: an investigation of the 2017-2019 measles outbreak in the northern region of Vietnam.

BACKGROUND: Measles remains a major public health burden worldwide. Parents often hesitate to vaccinate children with chronic diseases. We investigated the association between the percentage of vaccination and chronic diseases and explore hospital infections' role in the 2017-2019 measles outbreak across northern Vietnam provinces. METHODS: A total of 2,064 children aged 0-15 years old admitted for measles to the National Children's Hospital during the outbreak were included in the study. Demographic information, clinical characteristics, vaccination statuses and laboratory examination were extracted from electronic medical records, vaccination records, or interviews with parents when other sources were unavailable. RESULTS: The incidence rate that provincial hospitals sent to the National Children's Hospital was proportional to the population density of their provinces of residence. Early nosocomial transmission of measles was observed before community-acquired cases emerged in many provinces. Among patients aged over 18 months, those with chronic diseases had a proportion of vaccination of 9.4%, lower than patients without chronic diseases at 32.4%. Unvaccinated patients had a higher proportion of hospital-acquired infections with aOR = 2.42 (1.65-3.65), p < 0.001 relative to vaccinated patients. The proportion of hospital-acquired infections was higher among children with chronic diseases compared to those without, with aOR = 3.81 (2.90-5.02), p < 0.001. CONCLUSION: Measles spread in healthcare settings prior to community cases that occurred in several provinces. We recommend enhancing hospital infection control by increasing staff training and improving early detection and isolation during non-outbreak periods. Measles patients with chronic diseases exhibited lower proportions of vaccination and faced a higher risk of hospital-acquired infections. It is crucial to establish comprehensive vaccination guidelines and enhance parental awareness regarding the significance and safety of measles vaccination to protect these vulnerable individuals.

Impact of the COVID-19 Pandemic on Measles Vaccination Coverage and Estimated Catch-up Efforts for Serbia.

BACKGROUND: Measles is highly infectious, requiring ≥95% vaccine coverage rate (VCR) to prevent outbreaks. This study aimed to understand the impact of the COVID-19 pandemic on routine measles-containing vaccine (MCV) VCRs in Serbia and estimate national and regional catch-up vaccination required to prevent outbreaks. METHODS: A multiplier model was used to calculate annual MCV dose 1 (MCV1) and MCV dose 2 (MCV2) VCRs for children 1-6 and 6-12 years of age, respectively, for 2011-2022. Postpandemic (2023-2024) VCRs were modeled. The numbers of administered doses were compared to prepandemic and postpandemic, and monthly catch-up rates were calculated for 12-, 18- and 24-month campaigns. RESULTS: Between prepandemic and pandemic periods, national MCV1 VCR decreased from 88% to 81%, while MCV2 VCR decreased from 92% to 89%, corresponding to 20,856 missed MCV1 and 8760 missed MCV2 doses. Assuming national VCRs returned to prepandemic levels post-2022, 18% of children 1-6 years of age and 11% of children 6-12 years of age would have missed their MCV1 and MCV2 doses, respectively, by 2024. To catch up missed doses under this scenario, most regions would require monthly catch-up rates of 25%, 16% or 12% for MCV1 and 14%, 9% or 7% for MCV2, considering 12-, 18- or 24-month campaigns, respectively. CONCLUSIONS: The pandemic negatively impacted MCV VCRs in Serbia, leaving a sizeable proportion of children with missed doses. Significant catch-up efforts are required to recover VCRs to prepandemic levels and avoid future measles outbreaks, with increased monthly administration rates versus those in prepandemic periods.

Measles immunity status in Iranian infants and children and outbreak concerns: Time for reconsidering the vaccination schedule?

INTRODUCTION: Measles vaccination has greatly reduced the disease burden worldwide, but challenges remain due to variations in vaccine effectiveness across age groups. This study aimed to assess the serological profile of measles antibodies across different age groups, evaluate the impact of maternal immunity on antibody levels in infants under 12 months, and assess measles immunity in vaccinated individuals. MATERIAL AND METHODS: This cross-sectional study was conducted from June 2022 to January 2023 at the Children's Medical Center, a referral hospital in Iran. Serum samples were tested for measles-specific IgG and IgM antibodies using a commercial enzyme-linked immunosorbent assay (ELSA). An avidity assay was performed to assess measles virus-specific IgG antibodies on the samples that were positive and borderline for the measles IgG ELISA. RESULTS: The study included 969 participants across various age groups. Among them, 23% (221 out of 953) tested positive for measles IgM ELISA, and 52% (504 out of 969) for measles IgG ELISA. Regarding the avidity assay for measles virus-specific IgG, the majority (418 out of 573, 73%) showed high-avidity antibodies. Measles-specific IgG levels varied significantly across different age groups, with infants below 6 months old showing a mean IgG level of 477 mIU/mL, declining to 230 mIU/mL between 6 and 12 months, and increasing significantly to 683 mIU/mL in the 12 to 18 month age group, reaching a peak at 938 mIU/mL among children aged 18-72 months. CONCLUSION: The increasing IgM positivity among young Iranians suggests a rising risk of measles outbreaks, possibly due to vaccination gaps. Inadequate antibody levels in infants raise concerns about vaccination effectiveness. Considering declining maternal antibodies, vaccinating infants at 6-9 months could be beneficial. Boosters for adolescents and women may further mitigate outbreak risks.

Onward transmission of measles virus among vaccinated cases in a large community outbreak in Auckland, New Zealand, 2019.

BACKGROUND: Isolation of cases and quarantining of non-immune contacts are the mainstay of measles outbreak management in elimination settings. Serology testing of exposed contacts may not be feasible in large outbreaks; therefore, vaccination history is used as a proxy for determining immunity to measles and thus prevention of onward virus transmission. This study sought to investigate the risk of measles virus transmission from individuals with a history of one or two doses of measles-containing vaccine (MCV). METHODS:  Retrospective analysis of data from measles cases reported to Auckland Regional Public Health Service during the 2019 Auckland region measles outbreak. Vaccination history was verified using patient records and the New Zealand National Immunisation Register. Onward transmission was determined through case interviews and assessment of exposed contacts. RESULTS:  1451 measles cases were assessed as eligible for vaccination at the time of measles outbreak. Of these, 1015 (70.0%) were unvaccinated, 220 (15.2%) had unknown vaccination status, 139 (9.6%) had received only one dose of MCV and 77 (5.3%) had received two doses of the vaccine. Compared to unvaccinated cases, the odds of onward transmission were lower among those with one dose only (OR 0.41, 95% CI: 0.20-0.75) or two doses of MCV (OR 0.44, 95% CI: 0.17-0.95). Median time since vaccination was longer among those with onward transmission compared to those without onward transmission for one and two doses of the vaccine, suggesting a potential effect of waning immunity among this cohort. CONCLUSION:  These findings support the hypothesis that measles cases with a history of prior vaccination are less likely to transmit the virus to others compared to unvaccinated cases. Such information can be used to support decisions around quarantine requirements for vaccinated contacts in future measles outbreaks.

Onward Virus Transmission after Measles Secondary Vaccination Failure.

Measles in persons with secondary vaccination failure (SVF) may be less infectious than cases in unvaccinated persons. Our systematic review aimed to assess transmission risk for measles after SVF. We searched PubMed, Embase, and Web of Science databases from their inception dates. Inclusion criteria were articles describing persons who were exposed to measles-infected persons who had experienced SVF. Across the included 14 studies, >3,030 persons were exposed to measles virus from SVF cases, of whom 180 were susceptible, indicating secondary attack rates of 0%-6.25%. We identified 109 cases of SVF from the studies; 10.09% (n = 11) of case-patients transmitted the virus, resulting in 23 further cases and yielding an effective reproduction number of 0.063 (95% CI 0.0-0.5). These findings suggest a remarkably low attack rate for SVF measles cases, suggesting that, In outbreak situations, public health management of unvaccinated persons could be prioritized over persons with SVF.

Epidemiologic Analysis of a Postelimination Measles Outbreak in Central Ohio, 2022-2023.

Importance: Postelimination outbreaks threaten nearly a quarter century of measles elimination in the US. Understanding these dynamics is essential for maintaining the nation's measles elimination status. Objective: To examine the demographic characteristics and transmission dynamics of the 2022 to 2023 central Ohio measles outbreak. Design, Setting, and Participants: This cross-sectional study used electronic medical records and publicly available measles reports within an extensive central Ohio primary care network involving inpatient and outpatient settings. Participants included 90 children in Ohio with confirmed measles cases in 2022. Exposure: The exposure of interest was confirmed measles cases in Ohio in 2022. This included 5 internationally imported cases and 85 locally acquired cases. Main Outcomes and Measures: The primary outcome involved documenting and analyzing confirmed measles cases in Ohio in 2022, focusing on demographic characteristics, immunization status, and transmission links in outbreak-related cases. Results: This study analyzed 90 measles cases (47 [52.2%] male participants) in Ohio during 2022. Most participants self-identified as African or American Black (72 [80.0%]), with additional race categories including Asian, Hispanic, multirace (6 [6.7%]), White, and unknown (6 [6.7%]). Most participants were of Somali descent (64 [71.1%]), with additional ethnicity categories including American (16 [17.8%]), Guatemalan, Nepali, and unknown (6 [6.7%]). Participants were predominantly younger than 6 years (86 [95.5%]), unimmunized (89 [98.9%]), and resided in Franklin County, Ohio (83 [92.2%]). Prior to November 20, 2022, all cases occurred among unimmunized children of Somali descent in the Columbus area. Nosocomial superspreading events expanded the outbreak beyond the initially affected community. Conclusions and Relevance: This cross-sectional study of measles cases in Ohio during 2022 found that the outbreak primarily affected unimmunized children of Somali descent, highlighting the necessity for culturally tailored public health strategies to maintain measles elimination in the US. These findings underscore the importance of implementing targeted interventions and enhancing community engagement to increase vaccination rates.

A historical syndemic? The impact of synergistic epidemics of measles and scarlet fever on life expectancy in Victoria, Australia (1860s-1870s).

OBJECTIVES: To explore whether synergistic epidemics of measles and scarlet fever in 1860s-1870s Victoria, Australia could be characterized as syndemics, we apply the methods of Sawchuk, Tripp, and Samakaroon (Social Science & Medicine 2022, 295, 112956) to quantify the impact of each of the two major co-occurring epidemic events (1867, 1875) in terms of life expectancy (LE) changes. Sawchuk et al. posit the presence of a harvesting effect, indicated by a statistically significant increase in LE in the immediate post-epidemic "fallow period", as a criterion for identification of a historical syndemic. We test an alternate hypothesis that the same methods can identify a short-term scarring effect. MATERIALS AND METHODS: Using annual age- and cause-specific death statistics and census population data, we constructed abridged period life tables for baseline period, potential syndemic year, and "fallow" year for each of the two periods (1860s and 1870s). We compared LE at birth using Z-tests. We decomposed age-cause-specific mortality according to Arriaga's method to identify age-and cause-specific contributions to LE change. RESULTS: LE was significantly lower than baseline (1864-1865) in 1867 but not in the "fallow" year (1869). LE in 1875 and the 1878 "fallow" year were both significantly below baseline (1871-1873). Age-cause-specific decomposition showed similar patterns for 1867 and 1875 for measles and scarlet fever combined effects. DISCUSSION: Evidence of a scarring effect following the 1875 measles/scarlet fever combined peak supports the interpretation of this event as a syndemic. We suggest the short-term scarring effect can be a useful additional criterion for identifying historical syndemics.

Measles Outbreak Investigation in Aneded District, Northwest Ethiopia: A Case-Control Study.

BACKGROUND: Between 2000 and 2018, global measles deaths decreased by 73%, but the disease remains prevalent in many developing countries, especially in Africa and Asia. Although Ethiopia was attempting to eliminate the measles, it still ranks fourth in the world in terms of the number of cases. The aim of the investigation was to describe the outbreak and identify its determinants in the Aneded district. METHODS: Between March 3, 2020, and April 2, 2020, the 89 patients and 178 controls participated in a case-control study. Data were gathered by means of in-person interviews with household leaders. The attack and case fatality rates were determined. In multivariable logistic regression analysis, variables having a p-value of less than 0.05 were considered statistically significant cut-off points. RESULTS: An investigation was conducted on a total of 89 measles cases, with 3 deaths and 178 controls. In total, there were 1.65 attacks per 1000 people, or 3.4% of the case fatality rate. There were 155 days of outbreak duration. The disease was significantly associated with being female [adjusted odds ratios (AOR) = 2.66; 95% confidence interval (CI) = 1.38-5.11], under 5 years old [AOR = 7.24; 95% CI = 2.58-20.31], positive in attitude [AOR = 0.22; 95% CI = 0.11-0.42], and having a contact history [AOR = 3.19; 95% CI = 1.67-6.10]. CONCLUSION: The measles outbreak, with its higher attack and case fatality rate, has been influenced by factors like household attitudes, age, sex, contact and travel history and needs to be reduced through early detection, active surveillance, and fostering favorable attitudes towards disease prevention and control.

The Resurgence of Measles: A Rash From the Past.

Measles, or rubeola, remains a highly contagious infectious disease with a concerning resurgence in the United States. Despite previous control efforts, the number of reported cases continues to rise, surpassing the total for the previous year in just the first quarter of 2024 (CDC, 2024a). Emergency nurse practitioners and other emergency clinicians are likely to encounter patients presenting with concerns of or exposure to measles. However, given the low frequency of cases in the past, many emergency clinicians have likely not previously encountered measles, making identification more challenging. Early recognition and isolation are paramount in containing the spread of this virus and mitigating potential complications. This article aims to provide a review of measles, covering its pathophysiology, clinical presentations, and recommended management strategies for suspected or confirmed cases in emergency care settings.

Challenges for Sustaining Measles Elimination: Post-Verification Large-Scale Import-Related Measles Outbreaks in Mongolia and Cambodia, Resulting in the Loss of Measles Elimination Status.

The Western Pacific Region's pursuit of measles elimination has seen significant progress and setbacks. Mongolia and Cambodia were the first two middle-income countries in the Western Pacific to be verified as having eliminated measles by the Western Pacific Regional Verification Commission for Measles and Rubella Elimination, in March 2014 and 2015, respectively. However, both countries experienced large-scale or prolonged importation-related measles outbreaks shortly afterwards, leading to the re-establishment of endemic transmission. We describe the path to initial elimination in both countries and explore these outbreaks' characteristics, factors contributing to the loss of elimination status, and implications for broader elimination efforts. Data sources include case-based epidemiological and laboratory surveillance reports, historical immunization coverage, genotype data, and published reports of in-depth outbreak investigations. In Mongolia, a single prolonged and large-scale outbreak revealed a hidden immunity gap among young adults and was driven in part by nosocomial transmission, leading to significant morbidity and mortality and loss of elimination status. Cambodia suffered multiple importations from neighboring endemic countries during the global measles resurgence in 2018-2019, complicated by cross-border mobility and significant nosocomial amplification, and the country was ultimately unable to sufficiently distinguish independent chains of transmission, leading to loss of elimination status. Our findings highlight the importance of broadening population immunity assessments beyond children to include adults and specific high-risk groups. Robust routine immunization programs, supplemented by tailored SIAs, are crucial for preventing and managing outbreaks. Additionally, strong outbreak preparedness plans, rapid response strategies, and cross-border collaboration and the global effort to prevent multiple resurgences and large-scale importation-induced outbreaks are vital for maintaining elimination status. The experiences of Mongolia and Cambodia underscore the challenges of sustaining measles elimination in the face of importation risks, shared borders with endemic countries, healthcare system gaps, and population movements. Strengthening the global coordination and synchronization of measles elimination activities is imperative to protect the gains achieved and prevent future setbacks.

Characteristics of patients admitted to the intensive care unit during the 2019 measles epidemic in Samoa: A retrospective clinical case series.

Our report describes the characteristics of patients admitted to the intensive care unit of the National Hospital of Samoa during the 2019-2020 measles epidemic. The study design was a retrospective review of clinical records; the age range was 2 months to 51 years, with the majority of cases in the 2-23 month age group (71%). Vaccination status was unknown or unrecorded for 17 (24%). Of the 54 (75%) who were not fully vaccinated, 35 (65%) did not survive. Almost all (98%) presented with multiple complications on admission, mostly pneumonia (91%). The mortality rate was 61%, implying a low survival rate particularly among young infants and toddlers, even when optimal care was available and administered.

Measles Outbreak in Socioeconomically Diverse Sections: A Review.

Measles outbreaks among socioeconomically weaker sections constitute a significant public health challenge. The objective is to highlight the specific vulnerabilities and contributing factors that make these communities more susceptible to measles outbreaks. Socioeconomically weaker sections, often characterized by poverty, inadequate healthcare access, overcrowding, and suboptimal immunization rates, face heightened risks of measles outbreaks. These outbreaks occur due to various interrelated factors, including limited healthcare infrastructure, low vaccine coverage, a lack of awareness about vaccination benefits, and difficulties in accessing healthcare services. The effects of measles outbreaks in socioeconomically disadvantaged areas are critical. Particularly among vulnerable groups, including newborns, expectant mothers, and malnourished people, measles increases morbidity and mortality. There is also a considerable financial impact on the healthcare system and the afflicted families. Measles outbreaks in these populations must be addressed using a diversified strategy. In order to improve vaccine coverage through targeted immunization programs, raise community vaccination awareness, and address social determinants of health, efforts should concentrate on bolstering the healthcare infrastructure. Effective epidemic control and prevention depend on coordinated efforts by healthcare practitioners, legislators, local leaders, and public health groups. Healthcare systems can lessen the impact of measles in socioeconomically disadvantaged areas and strive toward attaining equitable health outcomes for all populations by addressing the socioeconomic variables that lead to the vulnerability of measles.