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.

Association Between Clinical Severity, Neuroimaging, and Electroencephalographic Findings in Children with Subacute Sclerosing Panencephalitis.

BACKGROUND: Children diagnosed with subacute sclerosing panencephalitis (SSPE) display a range of neuroimaging abnormalities during different stages of the disease, but their exact clinical significance remains unclear. METHODS: In this retrospective cohort study, our objective was to examine magnetic resonance imaging (MRI) abnormalities in the brains of patients aged 18 years or younger with subacute sclerosing panencephalitis. We aimed to correlate these MRI abnormalities with clinical severity, sociodemographic variables, electroencephalographic (EEG) abnormalities, and cerebrospinal anti-measles antibody titers. RESULTS: The study included 112 cases of subacute sclerosing panencephalitis (mean age at onset: 8.9 ± 2.6 years). MRI analysis at the time of presentation revealed the following abnormalities: subcortical white matter signal changes (n = 95), periventricular white matter signal changes (n = 76), splenium of corpus callosum involvement (n = 39), diffuse corpus callosum involvement (n = 27), cerebral atrophy (n = 35), basal ganglia involvement (n = 10), and brain stem involvement (n = 2). Notably, subcortical white matter involvement, periventricular white matter involvement, diffuse corpus callosum involvement, and basal ganglia involvement were more prevalent in patients with stage III and IV subacute sclerosing panencephalitis (P < .05 for all). Cerebral atrophy was also significantly more common in patients with stage III compared to those with stage IV subacute sclerosing panencephalitis (P < .0001). However, no substantial positive or negative associations were found between MRI findings and EEG abnormalities, other sociodemographic/clinical variables, and cerebrospinal fluid measles-specific antibody titers (P > .05). CONCLUSION: Early in the disease progression of subacute sclerosing panencephalitis, the temporoparietal and parietooccipital regions of the subcortical white matter are affected. Neuroimaging abnormalities exhibit a stronger association with Jabbour's clinical staging, but do not show significant associations with other clinical, sociodemographic, and EEG features.

Predicting the Airborne Transmission of Measles: Impact of Indoor Carbon Dioxide (CO2) Levels and Mitigation Strategies.

BACKGROUND: Measles is a highly contagious cause of febrile illness typically seen in young children. It is transmitted primarily through respiratory droplets and small-particle aerosols and can remain viable in the air. Despite the availability of an effective vaccine, measles remains a major global issue, particularly in regions with low vaccination rates. AIM: This study aimed to quantify the airborne transmission risk of the measles virus in various indoor environments. METHODS: Using indoor carbon dioxide (CO2) levels, we estimated the probability of airborne transmission and the basic reproduction number (Ro) in four hypothetical indoor scenarios, including restaurants, mass gathering events, homes, and business meetings, based on the modified Wells-Riley model. RESULTS: The relationship between airborne transmission rates and indoor CO2 concentrations was visualized, with and without mask usage. Without masks, at an indoor CO2 concentration of 1,000 ppm, the airborne transmission rates were high in homes (100.0%) and business meetings (100.0%) and moderate in restaurants (45.6%) and live events (30.6%). By contrast, the Ro was high in audience-participatory live events (60.9%) and restaurants (13.2%), indicating a higher risk of cluster infections. DISCUSSION AND CONCLUSION: In all indoor environmental scenarios, a positive linear relationship was found between the risk of airborne transmission and indoor CO2 levels. The risk of airborne transmission varied significantly across scenarios, which was influenced by various parameters, such as mask usage, quality of ventilation, conversation, and exposure duration. This model suggests that the risk of airborne transmission of measles can be easily predicted using a CO2 meter.

Individual and contextual factors associated with measles infection in Malaysia: a multilevel analysis.

Objectives: Despite effective vaccination strategies, measles remains a global public health challenge. The study explored individual and contextual factors associated with measles infection in Malaysia from 2018 to 2022, informing the development of targeted public health interventions. Methods: This cross-sectional study utilised data from the Ministry of Health, the Department of Statistics, and the Department of Environment Malaysia. Multilevel logistic regression analysis was employed to examine individual-level factors, including age, sex, ethnicity, nationality, contact history, travel history, and vaccination status. Concurrently, contextual factors were assessed, encompassing district-level determinants such as population density, median household income, urbanisation, the number of health and rural clinics, vaccination rates, PM2.5 levels, relative humidity, and temperature, to determine their impact on measles infection risk. Results: Measles infection was significantly associated with various individual factors. These included age (adjusted odds ratio [aOR], 1.02; 95% confidence interval [CI], 1.02-1.03), ethnicity, non-Malaysian nationality (aOR, 34.53; 95% CI, 8.42-141.51), prior contact with a measles case (aOR, 2.36; 95% CI, 2.07-2.69), travel history (aOR, 2.30; 95% CI, 1.13-4.70), and vaccination status (aOR, 0.76; 95% CI, 0.72-0.79). Among contextual factors, urbanisation (aOR, 1.56; 95% CI, 1.16-2.10) and the number of clinics (aOR, 0.98; 95% CI, 0.97-0.99) were significant determinants. Conclusion: This multilevel logistic regression analysis illuminates the complexities of measles transmission, advocating public health interventions tailored to individual and contextual vulnerabilities. The findings highlight the need for a synergistic approach that combines vaccination campaigns, healthcare accessibility improvements, and socioeconomic interventions to effectively combat measles.

Immunogenicity of a peptide-based vaccine for measles: a pilot evaluation in a mouse model.

Although neutralizing antibody is an established correlate of protection for measles, T cell-mediated responses play at least two critical roles in immunity to measles: first, through provision of 'help' enabling robust humoral immune responses; and second, through clearance of measles virus-infected cells. Previously, we identified 13 measles-derived peptides that bound to human leukocyte antigen (HLA) molecules in Priess cells infected with measles virus. In this study, we evaluated the immunogenicity of these peptides in a transgenic mouse model. Our results demonstrated that these peptides induced Th1-biased immune responses at varying levels. Of the 13 peptides, the top four immunogenic peptides were further selected for a viral challenge study in mice. A vaccine based on a combination of these four peptides reduced morbidity and weight loss after viral challenge compared to placebo. Our results emphasize the potential of T cell-mediated, peptide-based vaccines against measles.

Indocyanine green angiography reveals choroidal hypoperfusion in subacute sclerosing panencephalitis (SSPE).

We report the choroidal findings on indocyanine green angiography (ICGA) in two cases of subacute sclerosing panencephalitis (SSPE). The two immunocompetent patients (31-year-old and 30-year-old Asian Indian males) presented with acute-onset rapidly progressing vision loss with findings of necrotizing retinitis involving the central macula. Both patients tested negative for serological evidence of herpes or varicella, and toxoplasma antibodies. The patients demonstrated high serum and cerebrospinal fluid titers of anti-measles antibody (and abnormal electroencephalogram in one patient) leading to the diagnosis of SSPE. ICGA of both patients revealed distinct "dark dots" which showed hypofluorescence in the early and late phases suggestive of choroidal involvement/hypoperfusion. Choroidal involvement in SSPE has not been evaluated before and must be considered in the pathological manifestations of the disease.

Structural basis of paramyxo- and pneumovirus polymerase inhibition by non-nucleoside small-molecule antivirals.

Small-molecule antivirals can be used as chemical probes to stabilize transitory conformational stages of viral target proteins, facilitating structural analyses. Here, we evaluate allosteric pneumo- and paramyxovirus polymerase inhibitors that have the potential to serve as chemical probes and aid the structural characterization of short-lived intermediate conformations of the polymerase complex. Of multiple inhibitor classes evaluated, we discuss in-depth distinct scaffolds that were selected based on well-understood structure-activity relationships, insight into resistance profiles, biochemical characterization of the mechanism of action, and photoaffinity-based target mapping. Each class is thought to block structural rearrangements of polymerase domains albeit target sites and docking poses are distinct. This review highlights validated druggable targets in the paramyxo- and pneumovirus polymerase proteins and discusses discrete structural stages of the polymerase complexes required for bioactivity.

Measles second dose vaccine uptake and associated factors among under-five children in Jigjiga City, Somali Region, Eastern Ethiopia: a community-based cross-sectional study.

Background: Measles is one of the leading causes of under-five mortality and morbidity worldwide. Although the routine service for the second dose of the measles-containing vaccine (MCV2) was introduced in Ethiopia recently, there is a paucity of evidence regarding its coverage and the factors that hinder its uptake at both the local and national levels. Thus, this study aimed to assess the uptake of MCV2 and its associated factors among children aged between 15 and 36 months old in Jigjiga City, Somali Region, Ethiopia. Methods: A community-based cross-sectional study was conducted among 429 children aged between 15 and 36 months old with their mothers/caregivers in Jigjiga City from April 1 to May 1, 2023. A multistage sampling technique was used and data were collected by using structured interviewer-administered questionnaires. The collected data were entered into Epi-data version 3.2 and analyzed in a statistical package for the social sciences (SPSS) version 26. Bivariate and multivariable logistic regression analyses were performed to identify factors associated with the uptake of the measles second dose vaccine. An adjusted odds ratio with 95% CI were reported and statistical significance was declared at p < 0.05. Results: The coverage of MCV2 among children aged between 15 and 36 months was 21.4% (95% CI: 17.7, 25.2). The educational status of the mother (AOR = 3.154; 95% CI: 1.68, 5.93), place of delivery (AOR = 1.90; 95% CI: 1.08, 3.25), postnatal care visits of the mother (AOR = 2.40; 95% CI: 1.37, 4.22), time taken to reach a health facility (AOR = 2.67; 95% CI: 1.28, 5.57), and knowledge about child vaccination (AOR = 2.43; 95% CI: 1.45, 4.08) were factors significantly associated with the uptake of the measles second dose vaccine. Conclusion: The coverage of MCV2 in the study area was low compared to the national immunization targets. Educational status of the mother/caregivers, place of delivery, postnatal care visits of the mother, time to reach a health facility, and knowledge about vaccination of children were significantly associated with measles second dose vaccination. The focus should be given to improving the awareness of mothers on the importance of child vaccination to improve the uptake of measles second dose vaccine and reduce the burden of measles in the region.

Quantifying the long-term effects of measles infection - A retrospective cohort study.

OBJECTIVE: To assess whether measles infection has an impact on the rate of non-measles infectious diseases over an extended period. METHODS: This retrospective matched cohort study included 532 measles diagnosed patients which were exactly matched with 2,128 individuals with no previous measles diagnosis. Adjusted Odds ratio for any all - cause infectious diagnosis and any viral infection diagnosis, up to 2 years post measles diagnosis, between the measles and control groups was obtained from a conditional logistic regression model. Cox proportional hazards model was employed to estimate the hazard ratio. RESULTS: - Previous measles (MeV) exposure was associated with an increased risk for all-cause non-measles infectious disease diagnosis (OR = 1.83, 95% CI 1.26-2.64, p = 0.001), with 492 diagnoses in the MeV-exposed group and 1868 diagnoses in the control group. Additionally, previous MeV exposure was linked to a higher risk of viral infection diagnosis (OR = 1.23, 95% CI 1.01-1.59, p < 0.05), with 302 viral infection diagnoses in the MeV-exposed group and 1107 diagnoses in the control group. The hazard ratio for viral diagnosis in the MeV-exposed group compared to the control group was 1.54 (95% CI 1.18-2.02, p < 0.001). CONCLUSION: Individuals diagnosed with measles had a moderate increased risk of being diagnosed with all cause non-measles infectious disease or viral infection. This observational individual level study supports previous ecological and individual population level studies.

Cytokine Storm Syndrome Associated with Hemorrhagic Fever and Other Viruses.

A wide variety of infections can trigger cytokine storm syndromes including those caused by bacteria, viruses, fungi and parasites. The most frequent viral trigger is Epstein-.Barr virus which is covered in Chapter 16. CSS associated with COVID-19 is also discussed separately (Chapter 22). This chapter will focus on other viruses including the hemorrhagic fever viruses, influenza, parainfluenza, adenovirus, parvovirus, hepatitis viruses, measles, mumps, rubella, enterovirus, parechovirus, rotavirus, human metapneumovirus and human T-lymphotropic virus. The published literature consists of many single case reports and moderate-sized case series reporting CSS, in most circumstances meeting the 2004 diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH). There is no published clinical trial evidence specifically for management of HLH associated with these viruses. In some situations, patients received supportive therapy and blood product transfusions only but in most cases, they were treated with one or more of intravenous corticosteroids, intravenous immunoglobulin and/or etoposide. These were successful in many patients although in significant numbers progression of infection to CSS was associated with mortality.

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.

Modeling measles transmission in adults and children: Implications to vaccination for eradication.

Despite the availability of successful vaccines, measles outbreaks have occurred frequently in recent years, presumably due to the lack of proper vaccination implementation. Moreover, measles cases in adult groups, albeit small in number, indicate that the previously neglected adult group may need to be brought into vaccine coverage to achieve WHO's goal of measles eradication from the globe. In this study, we develop a novel transmission dynamics model to describe measles cases in adults and children to evaluate the role of adult infection in persistent measles cases and vaccination programs for eradication. Analysis of our model, validated by measles cases from outbreaks in Nepal, provides the vaccination reproduction number (conditions for measles eradication or persistence) and the role of contact network size. Our results highlight that while children are primary targets for measles outbreaks, a small number of infections in adults may act as a reservoir for measles, causing obstacles to eradication. Furthermore, our model analysis shows that while impactful controls can be achieved by children-focused vaccines, a combined adult-child vaccination program may help assert eradication of the disease.

Assessing the impact of COVID-19 on routine immunization in Sierra Leone.

BACKGROUND: The COVID-19 pandemic had a profound impact on healthcare systems and services, including routine immunization (RI). To date, there is limited information on the effects of the COVID-19 pandemic on RI in West African countries such as Sierra Leone, which had already experienced public health emergencies that disrupted its healthcare system. Here, we describe the impact of the COVID-19 pandemic on the RI of key antigens in Sierra Leone. METHODS: We used vaccination data from the District Health Information System for BCG, measles-rubella 1 and 2, and pentavalent 1 and 3 antigens. We compared 2019, 2020, 2021, and 2022 annual coverage rates for the selected antigens at the national and district levels. We used the Pearson chi-square test to assess the difference between annual coverage rates between 2019 and 2020, 2020-2021, and 2021-2022. RESULTS: National coverage rates for all antigens declined in 2019-2020, notably measles-rubella 1 and pentavalent 3 (-5.4% and - 4.9%). Between 2020 and 2021, there was an overall increase in coverage (+ 0.2% to + 2.5%), except for measles-rubella 2 (-1.8%). Measles-rubella antigens rebounded in 2021-2022, while others decreased between - 0.5 and - 1.9% in coverage. Overall, all district-level coverage rates in 2022 were lower than those in 2019. Most districts decreased between 2019 and 2022, though a few had a continuous increase; some had an increase/recovery between 2020 and 2021; some districts had recovered 2019 levels by 2022. CONCLUSION: The COVID-19 pandemic impacted Sierra Leone's national BCG, measles-rubella, and pentavalent antigen immunization, which were not fully restored in 2022. Most districts experienced notable coverage declines during the pandemic, though a few reached or surpassed 2019 rates in 2022. Examining pandemic impact can benefit from a focus beyond the national level to identify vulnerable regions. Sierra Leone's post-pandemic RI reestablishment needs targeted strategies and continual investments for equitable access and coverage, as well as to prevent vaccine-preventable diseases.

Regional disparities in measles vaccination coverage and their associated factors: an ecological study in Japan.

BACKGROUND: The decline in measles vaccination coverage is a global concern. In Japan, coverage of the first-dose of measles vaccine, which had exceeded the target of 95.0% since fiscal year (FY) 2010, fell to 93.5% in FY 2021. Vaccination coverage increased to 95.4% in FY 2022 but varied by municipality. Few studies have focused on regional disparities in measles vaccination coverage. This study aimed to clarify the regional disparities in measles vaccination coverage by municipality in Japan and their associated factors. METHODS: In this ecological study, the measles vaccination coverage in FY 2022; population density; area deprivation index (ADI, an indicator of socioeconomic status); proportion of foreign nationals, single-father households, single-mother households, and mothers aged ≥30 years; and number of medical facilities, pediatricians, and non-pediatric medical doctors in 1,698 municipalities were extracted from Japanese government statistics. Negative binomial regression was performed with the number of children vaccinated against measles as the dependent variable, number of children eligible for measles vaccination as the offset term, and other factors as independent variables. RESULTS: Vaccination coverage was less than 95.0% in 54.3% of municipalities. Vaccination coverage was significantly positively associated with population density and negatively associated with the proportion of single-father households, mothers aged ≥30 years, and the ADI (incidence rate ratio [IRR]: 1.004, 0.976, 0.999, 0.970, respectively). CONCLUSION: This study showed regional disparities in measles vaccination coverage in Japan. Single-father households, age of mothers, and socioeconomic status may be key factors when municipalities consider strategies to improve vaccination coverage.

The Epidemiological Characteristics and Spatiotemporal Clustering of Measles - China, 2005-2022.

Introduction: In recent years, the incidence of measles in China has consistently remained below 1 per 100,000 population, yet the disease has not been eliminated. This study aims to comprehensively analyze the epidemiological characteristics of measles from 2005 to 2022, identify high-risk populations and areas, and propose targeted interventions. Methods: We utilized data from the China Disease Prevention and Control Information System for our comprehensive analysis. Spatial autocorrelation was employed to examine the spatial clustering of measles, while spatiotemporal scanning analysis was used to detect spatiotemporal clustering to describe measles epidemiology during the study period. Results: Between 2005 and 2022, 732,218 measles cases were reported in China. Overall, the incidence of measles exhibited a downward trend, particularly during the periods of 2008-2011 and 2015-2022. In 2022, the incidence rate reached its historical low at 0.039 per 100,000 population. Measles predominantly affects young children. Since 2017, global spatial clustering has diminished, although hotspot areas persist in the western provinces. Spatial-temporal scanning identified a high-incidence cluster from 2005 to 2008, comprising 15 provinces in the western, central, and northern regions of China. Conversely, from 2016 to 2022, a low-incidence cluster was detected in the southern and central provinces. Conclusions: China has made significant progress in measles prevention and control. The recent low incidence and absence of substantial spatiotemporal clustering indicate that China is nearing measles elimination. However, there is a continuing need to enhance prevention and control efforts among very young children and in historic incidence hotspots in western provinces. Additionally, improving the diagnosis of vaccine-associated rash illnesses is essential.

Measles outbreak in 2019: a warning for the post-COVID-19 pandemic period.

Introduction. At the end of 2019 and the year before, there was a significant spread of measles in the World Health Organization (WHO) European Region.Gap statement. Among the countries that reported, a measles outbreak was Bosnia and Herzegovina (BiH).Aim. To describe the measles outbreak in BiH (an entity of the Federation of BiH, FBiH) in 2019.Methodology. Confirmatory IgM serology, measles nucleic acid detection by real-time RT-PCR and virus genotyping were done in the WHO-accredited laboratory for measles and rubella at the Clinical Center of the University of Sarajevo, Unit for Clinical Microbiology. Genotype was determined in all measles-RNA-positive cases by sequence analysis of the 450 nt fragment coding the C-terminal of measles virus nucleoprotein (N).Results. From 1 January to 31 December 2019, 1332 measles cases were reported, with the peak observed in April 2019 (413/1332, 31.01 %). Sarajevo Canton had the highest incidence, number of cases and percentage (206.4; 868/1332; 65.17 %) of measles cases. Around four-fifths of infected persons were unvaccinated (1086/1332, 81.53 %), while 4.58 % of the patients (61/1332) were immunized with one dose of measles-containing vaccine. The highest proportion of cases was found in children 0-6 years of age (738/1332, 55.41 %). Measles IgM positivity was determined in 75.88 % (346/456), while virus RNA was detected in 82.46 % (47/57) of the swab samples. All measles virus sequences belonged to genotype B3. SNP (position 216: C=>T) was detected in 1 of the 40 sequences obtained during this outbreak.Conclusion. Due to suboptimal immunization coverage, BiH belongs to countries at a high risk for measles outbreaks. Post-COVID-19 (coronavirus disease 2019) pandemic, targeted and tailored strategies are required to ensure routine vaccination demand and acceptance and broad partner and stakeholder group participation.

Interplay between oncolytic measles virus, macrophages and cancer cells induces a proinflammatory tumor microenvironment.

Attenuated measles virus (MV) exerts its oncolytic activity in malignant pleural mesothelioma (MPM) cells that lack type-I interferon (IFN-I) production or responsiveness. However, other cells in the tumor microenvironment (TME), such as myeloid cells, possess functional antiviral pathways. In this study, we aimed to characterize the interplay between MV and the myeloid cells in human MPM. We cocultured MPM cell lines with monocytes or macrophages and infected them with MV. We analyzed the transcriptome of each cell type and studied their secretion and phenotypes by high-dimensional flow cytometry. We also measured transgene expression using an MV encoding GFP (MV-GFP). We show that MPM cells drive the differentiation of monocytes into M2-like macrophages. These macrophages inhibit GFP expression in tumor cells harboring a defect in IFN-I production and a functional signaling downstream of the IFN-I receptor, while having minimal effects on GFP expression in tumor cells with defect of responsiveness to IFN-I. Interestingly, inhibition of the IFN-I signaling by ruxolitinib restores GFP expression in tumor cells. Upon MV infection, cocultured macrophages express antiviral pro-inflammatory genes and induce the expression of IFN-stimulated genes in tumor cells. MV also increases the expression of HLA and costimulatory molecules on macrophages and their phagocytic activity. Finally, MV induces the secretion of inflammatory cytokines, especially IFN-I, and PD-L1 expression in tumor cells and macrophages. These results show that macrophages reduce viral proteins expression in some MPM cell lines through their IFN-I production and generate a pro-inflammatory interplay that may stimulate the patient's anti-tumor immune response.

Qualitative Insights on Barriers to Receiving a Second Dose of Measles-Containing Vaccine (MCV2), Oromia Region of Ethiopia.

Introduction: Ethiopia introduced a second dose of measles-containing vaccine (MCV2) in 2019 to provide further protection against measles and further progress toward elimination. However, the sub-optimal coverage of both MCV1 and MCV2 suggest challenges with vaccine uptake. In this qualitative study, we explored barriers to the uptake of MCV2 among caregivers, community leaders, and healthcare workers (HCWs). Method: A qualitative study was conducted between mid-April and mid-May 2021. We selected ten woredas (districts) in the Oromia Region, Ethiopia, stratified by settlement type (urban/rural), MCV1 coverage (high ≥ 80%; low < 80%), and history of measles outbreaks between June 2019 and June 2020. Experiences surrounding barriers to MCV2 uptake were discussed via focus group discussions (FGDs) and in-depth interviews (IDIs) with caregivers of children 12-23 and 24-36 months and key informant interviews (KIIs) with HCWs who administer vaccines and with community leaders. Participants were recruited via snowball sampling. Recorded data were transcribed, translated to English, and analyzed using ATLAS.ti v.09. Results: Forty FGDs and 60 IDIs with caregivers, 60 IDIs with HCWs, and 30 KIIs with community leaders were conducted. Barriers among caregivers included lack of knowledge and awareness about MCV2 and the vaccination schedule, competing priorities, long wait times at health facilities, vaccine unavailability, negative interactions with HCWs, and transportation challenges. At the community level, trusted leaders felt they lacked adequate knowledge about MCV2 to address caretakers' questions and community misconceptions. HCWs felt additional training on MCV2 would prepare them to better respond to caretakers' concerns. Health system barriers identified included the lack of human, material, and financial resources to deliver vaccines and provide immunization outreach services, which caretakers reported as their preferred way of accessing immunization. Conclusions: Barriers to MCV2 uptake occur at multiple levels of immunization service delivery. Strategies to address these barriers include tools to help caretakers track appointments, enhanced community engagement, HCW training to improve provider-client interactions and MCV2 knowledge, and efforts to manage HCW workload.

Persistence of Antibodies against Measles, Mumps, and Rubella after the Two-Dose MMR Vaccination: A 7-Year Follow-Up Study.

In 2014, the Expanded Program on Immunization of Thailand changed the timing of the second dose of the measles-mumps-rubella (MMR) vaccine from 4-6 years to 2.5 years, while maintaining the first dose at 9 months of age. This study aimed to examine the dynamics and durability of immune responses induced by the two-dose MMR vaccine in a group of 169 Thai children from 4 to 7 years of age (4.5 years after the second MMR dose). We followed a cohort of healthy children from a clinical trial (ClinicalTrials.gov NCT02408926) where they were administered either the Priorix vaccine (GlaxoSmithKline Biologicals, Rixensart, Belgium) or M-M-RII (Merck & Co., Kenilworth, NJ, USA) at 9 months and 2.5 years of age. Blood samples were collected annually from ages 4 to 7 years. Anti-measles, -mumps, and -rubella IgG levels were evaluated using the enzyme-linked immunosorbent assay (EUROIMMUN, Lubeck, Germany). A total of 169 children completed this study. Over the 4.5 years following the two-dose MMR vaccination, we observed a decline in the seroprotection rates against measles and mumps, but not rubella. Longitudinal monitoring of antibody persistence, among other strategies, will help predict population-level immunity and inform public health interventions to address potential future outbreaks.

Factors Associated with Uptake of Routine Measles-Containing Vaccine Doses among Young Children, Oromia Regional State, Ethiopia, 2021.

Recommended vaccination at nine months of age with the measles-containing vaccine (MCV1) has been part of Ethiopia's routine immunization program since 1980. A second dose of MCV (MCV2) was introduced in 2019 for children 15 months of age. We examined MCV1 and MCV2 coverage and the factors associated with measles vaccination status. A cross-sectional household survey was conducted among caregivers of children aged 12-35 months in selected districts of Oromia Region. Measles vaccination status was determined using home-based records, when available, or caregivers' recall. We analyzed the association between MCV1 and MCV2 vaccination status and household, caregiver, and child factors using logistic regression. The caregivers of 1172 children aged 12-35 months were interviewed and included in the analysis. MCV1 and MCV2 coverage was 71% and 48%, respectively. The dropout rate (DOR) from the first dose of Pentavalent vaccine to MCV1 was 22% and from MCV1 to MCV2 was 46%. Caregivers were more likely to vaccinate their children with MCV if they gave birth at a health facility, believe that their child had received all recommended vaccines, and know the required number of vaccination visits and doses. MCV2 coverage was low, with a high measles dropout rate (DOR). Caregivers with high awareness of MCV and its schedule were more likely to vaccinate their children. Intensified demand generation, defaulter tracking, and vaccine-stock management should be strengthened to improve MCV uptake.