Measles Vaccine Research Articles

β-lactamase and macrolide resistance gene carriage in E. coli isolates among children discharged from inpatient care in western Kenya: a cross-sectional study

Abstract Background Antimicrobial resistance (AMR) is a global threat to infectious disease control, particularly among recently hospitalized children. We sought to determine the prevalence and mitigating factors of resistance in enteric Escherichia coli among children discharged from health facilities in western Kenya. Methods Between June 2016 and November 2019, children aged 1-59 months were enrolled at the point of discharge from hospital. E. coli was isolated by microbiological culture from rectal swabs at baseline. β-lactamases and macrolide resistance-conferring genes were detected by PCR. The modified Poisson regression model was used to assess the predictors mph(A) and CTX-M-type ESBL. Results Of the 238 children whose E. coli isolates were tested, 91 (38.2%) and 109 (45.8%) had detectable CTX-M-type ESBL and mph(A) genes, respectively. Antibiotic treatment during hospitalization (adjusted prevalence ratio [aPR]=2.47; 95%CI:1.12-5.43, p=0.025), length of hospitalization (aPR=1.42; 95%CI:1.00-2.01, p=0.052), and the practice of open defecation (aPR=2.47; 95%CI:1.40-4.36, p=0.002) were independent predictors for CTX-M-type ESBL and for mph(A) genes. Pneumococcal vaccination was associated with a 43% lower likelihood of CTX-M-type ESBL (aPR=0.57; 95%CI:0.38-0.85, p=0.005), whilst measles vaccination was associated with a 32% lower likelihood of mph(A) gene (aPR=0.68; 95%CI:0.49-0.93, p=0.017) in E. coli isolates. Conclusions Among children discharged from hospital, history of vaccination, shorter hospital stay, lack of in-hospital antibiotic exposure and improved sanitation were associated with lower likelihood of AMR genes. AMR control programs should consider strategies beyond antimicrobial stewardship, including improvements in sanitation, increased vaccine coverage and the development of novel vaccines, to mitigate the continued spread of AMR.

Relationship between parental acceptance of the COVID-19 vaccine and attitudes towards measles vaccination for children: A cross-sectional study

BackgroundThe COVID-19 pandemic has led to decreased measles vaccination rates globally, exacerbating vaccine hesitancy. This study examines the relationship between COVID-19 vaccine acceptance and childhood measles vaccination among parents in Hong Kong. MethodsA cross-sectional online survey was conducted in Hong Kong from March to September 2022. Parents were recruited via the Qualtrics panel, and a total of 588 parents were invited via email or social media account to participate in the survey. We used the adjusted Measles-containing Vaccine Hesitancy Scale for the assessment of parental vaccine hesitancy for children. A multiple linear regression analysis was conducted to examine the association between parental acceptance of the COVID-19 vaccine and their attitudes towards childhood measles vaccination. ResultsOf the 588 participants, parents who have been vaccinated against COVID-19 exhibited significantly less measles-containing vaccine hesitancy comparing to those unvaccinated (β = −2.96, 95% confidence interval [CI]: −5.10 to −0.83, p = 0.007). Mothers exhibited more hesitancy compared to fathers (β = 1.64, 95% CI: 0.60 to 2.68, p = 0.002). Parents with a higher self-rated health (β = −2.20, 95% CI: −3.21 to −1.20, p < 0.001), or who have received advice from health professionals to offer measles, influenza, or COVID-19 vaccines for kids (β = −2.41, 95% CI: −3.49 to −1.32, p < 0.001) had lower levels of hesitancy. ConclusionCOVID-19 vaccine status of parents was associated with reduced hesitancy towards measles vaccines for their children. Addressing vaccine hesitancy effectively requires targeted communication strategies, particularly focusing on those unvaccinated and leveraging the influence of healthcare professionals.

Evaluating Scope and Bias of Population-Level Measles Serosurveys: A Systematized Review and Bias Assessment.

Measles seroprevalence data have potential to be a useful tool for understanding transmission dynamics and for decision making efforts to strengthen immunization programs. In this study, we conducted a systematized review and bias assessment of all primary data on measles seroprevalence in low- and middle-income countries (as defined by World Bank 2021 income classifications) published from 1962 to 2021. On 9 March 2022, we searched PubMed for all available data. We included studies containing primary data on measles seroprevalence and excluded studies if they were clinical trials or brief reports, from only health-care workers, suspected measles cases, or only vaccinated persons. We extracted all available information on measles seroprevalence, study design, and seroassay protocol. We conducted a bias assessment based on multiple categories and classified each study as having low, moderate, severe, or critical bias. This review was registered with PROSPERO (CRD42022326075). We identified 221 relevant studies across all World Health Organization regions, decades, and unique age ranges. The overall crude mean seroprevalence across all studies was 78.0% (SD: 19.3%), and the median seroprevalence was 84.0% (IQR: 72.8-91.7%). We classified 80 (36.2%) studies as having severe or critical overall bias. Studies from country-years with lower measles vaccine coverage or higher measles incidence had higher overall bias. While many studies have substantial underlying bias, many studies still provide some insights or data that could be used to inform modelling efforts to examine measles dynamics and programmatic decisions to reduce measles susceptibility.

How did the introduction of the measles-containing vaccine second dose (MCV2) affect measles vaccine uptake? – evidence from Nigeria

ABSTRACT Nigeria has the highest burden of measles worldwide, as measles vaccine uptake remains low. Recently, the second dose of the measles-containing vaccine (MCV2) was introduced as part of the routine immunization (RI) program, and this study examined how it changed the uptake of the measles vaccine and the factors associated with vaccination behavior. The Nigeria Multiple Indicator Cluster Survey (MICS) 2021 was used to compare measles vaccination uptake as well as factors associated with vaccination uptake between children before MCV2 introduction (cohort 1) and after the introduction (cohort 2). The overall rate of measles vaccine uptake was higher among cohort 1 (64%–95%) than among cohort 2 (56%–92%) in all zones because of younger age among cohort 2. The dropout from the first to second measles vaccines was similar between the cohorts (around 24%). Higher maternal education levels and higher household wealth levels were both correlated with the vaccine uptake or both cohorts but a positive correlation between the dropout and mother’s education level was observed only among cohort 2, especially in the North West and South West zones. The positive correlation between the dropout and mother’s education level among cohort 2 indicates that the introduction of MCV2 as part of RI might have helped to narrow the disparity in measles vaccine uptake in North West and South West zones. Further study is required to investigate strategies employed to reduce the disparity in these zones to apply nationwide.

Decadal analysis of measles epidemiological data in India (2011–2020)

BackgroundDespite India being one of the largest contributors to the measles burden, crucial epidemiological information is significantly lacking. We have analyzed the national-level representative data between 2011 and 2020 to estimate the national- and state-level incidence, first dose vaccine coverage, and mortality; and developed a prediction model to examine the trend of the disease.MethodsWe extracted the Health Management Information System (HMIS) for monthly aggregated measles cases, deaths, and child immunization (9–11 months) for first dose measles vaccine coverage across all states & Union Territories (UT). Population information & projections were extracted based on Census 2011. A multilevel fixed effect panel data model was used to predict measles incidence rate, assuming measles vaccination coverage as a predictor while accounting for time fixed effects.ResultsTotal 558,536 measles cases and 4209 measles deaths were reported in India between 2010 and 2020. The incidence rate was highest in 2013 (628.8/million population), followed by a significant decline to reach 52.0/million in 2020. Measles vaccination coverage for the first dose was 84.1% in 2011 to 91.3% in 2019. Higher vaccination coverage was significantly correlated (r = 0.7, p = 0.02) with decline of measles incidence rate. The case fatality rate (CFR) was least in 2014 (0.13%) but upsurged consistently reaching to 3.3% in 2020. The predictive model indicates that with a first-dose vaccine coverage of 93.5%, and keeping other factors constant, the national measles incidence is projected to reach zero by 2025.ConclusionMeasles incidence is declining in India due to higher vaccination coverage, yet the rise in death rates emphasizes the need for continued collaborative efforts to achieve a measles-free nation.

Measles Outbreak Associated with a Migrant Shelter - Chicago, Illinois, February-May 2024.

Measles, a highly contagious respiratory virus with the potential to cause severe complications, hospitalization, and death, was declared eliminated from the United States in 2000; however, with ongoing global transmission, infections in the United States still occur. On March 7, 2024, the Chicago Department of Public Health (CDPH) confirmed a case of measles in a male aged 1 year residing in a temporary shelter for migrants in Chicago. Given the congregate nature of the setting, high transmissibility of measles, and low measles vaccination coverage among shelter residents, measles virus had the potential to spread rapidly among approximately 2,100 presumed exposed shelter residents. CDPH immediately instituted outbreak investigation and response activities in collaboration with state and local health departments, health care facilities, city agencies, and shelters. On March 8, CDPH implemented active case-finding and coordinated a mass vaccination campaign at the affected shelter (shelter A), including vaccinating 882 residents and verifying previous vaccination for 784 residents over 3 days. These activities resulted in 93% measles vaccination coverage (defined as receipt of ≥1 recorded measles vaccine dose) by March 11. By May 13, a total of 57 confirmed measles cases associated with residing in or having contact with persons from shelter A had been reported. Most cases (41; 72%) were among persons who did not have documentation of measles vaccination and were considered unvaccinated. In addition, 16 cases of measles occurred among persons who had received ≥1 measles vaccine dose ≥21 days before first known exposure. This outbreak underscores the need to ensure high vaccination coverage among communities residing in congregate settings.

Results of treatment of patients with newly diagnosed immune thrombocytopenia: is it justified to follow clinical recommendations?

Immune thrombocytopenia (ITP) is an acquired immune-mediated disease characterized by isolated transient or persistent thrombocytopenia &lt; 100·109/L. The incidence of immune thrombocytopenia is 4–6,4 per 105 children/year.Purpose. To analyze the results of treatment newly diagnosed immune thrombocytopenia according to the clinical guidelines (ID699) published on the website of the Ministry of Health of Russia.Material and methods. The analysis included 13 patients (F–46%, M–54%, median age — 9.5 (4–17) years) with immune thrombocytopenia admitted to the Tver Regional children hospital in 2023. A history of infection preceding the immune thrombocytopenia was in 69% of cases and measles vaccination in 8%. The median period from the onset of infection was 11 (5–15) days. Degree of bleeding was — 1 gr. — 4 (31%), 2 gr. — 3 (23%), 3 gr. — 6 (46%). Hematuria was observed in 3 (23%), menorrhagia in 1 (8%) case. The mean platelet count at the time of admission was 9,0 (1.0–86) · 109/l.Results. The incidence was 5.7 per 105 children/year. Dexamethasone 20 mg/m2, days 1–3, was used in 54% of cases; IVIG 1000 mg/kg, day 1 in 15%, prednisolone 2 mg/kg, day 21 in 8% and in 23% of cases dynamic follow-up was performed. In 2 cases (17%), discontinuation of steroid therapy and switching to IVIG was required due to a hemorrhagic syndrome deterioration or/and complication of steroid therapy. Partial and complete responses were achieved in 8 (62%) and 4 (31%) cases respectively. In 1 (8%) case, the response could not be evaluated. The summary efficacy of first-line therapy was 92%.Conclusion. The clinical guidelines ID699 was highly effective in achieving a primary response and preventing recurrence of immune thrombocytopenia in children.

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.

Exploring landscape of measles vaccination coverage: A step towards measles elimination goal in India

IntroductionMeasles remains a critical public health concern causing significant morbidity and mortality globally. Despite the success of measles vaccination programs, challenges persist, particularly in India. This study investigates dose-wise measles vaccination coverage and explores gaps in immunization focusing on zero-dose, one-dose, and two-dose coverage among children aged 24–35 months. Data sources and methodologyThe National Family Health Survey 2019–21 (NFHS-5) served as the data source and the study analyzed information from 43,864 children aged 24–35 months. Sociodemographic variables such as birth order, wealth quintile, gender, social group, religion, residence, mother education, delivery-related factors, and media exposure were considered. Statistical analysis involved weighted estimates, chi-square tests, and multivariate multinomial logistic regression. ResultsThe study revealed that challenges persist in achieving optimal measles vaccination coverage. Analysis by sociodemographic factors highlighted disparities in coverage, with variations in zero dose prevalence across states and districts. The percentage of zero-dose children was significantly higher, with 11.5% of children in India remaining to receive any measles vaccination. Factors influencing vaccine coverage include birth order, age, wealth quintile, social group, religion, residence, maternal education, place of delivery, media exposure, and mode of delivery. The findings from the spatial analysis show the clustering of zero-dose children is high in the northeastern states of India. DiscussionMeasles zero-dose children pose a significant obstacle to achieving elimination goals. Spatial analysis identifies clusters of unvaccinated populations guiding targeted interventions. The study aligns with global initiatives such as the Immunization Agenda 2030 emphasizing equitable vaccine access and discusses how India can tailor its strategies to achieve the goal. Lessons from polio eradication efforts inform strategies for measles elimination, stressing the importance of high-quality data and surveillance. The study underscores the urgency of addressing last-mile measles vaccination gaps in India. Spatially targeted interventions informed by sociodemographic factors can enhance immunization coverage. Achieving measles elimination requires sustained efforts and leveraging lessons from successful vaccination campaigns. The study findings have the potential to contribute to informed decision-making, supporting India's roadmap for the measles and rubella elimination goal.

Vaccination against Measles in Patients with Oncological Disease

Relevance. Growing distrust of vaccines around the world, a decrease in vaccination rates have led to an increase in the incidence of measles and a rise in the vulnerability of people with immunodeficiency status. The aim. To study the efficacy and safety of measles vaccination in children with oncohematological diseases. Materials &amp; methods. The study involved 107 children: 74 of them with a history of acute lymphoblastic leukemia and 33 with solid tumors. All children had a history of receiving standardized polychemotherapy. In all the subjects, the vaccination history was studied, the titers of specific antibodies to measles were determined. Children with non-protective levels of antibodies (53 children) were subsequently vaccinated against measles. Results and discussions. Of the 107 children examined, before cancer, 99 (92.5%) were vaccinated against measles, of which 68 (68.7%) patients were only vaccinated, and 31 (31.3%) had vaccination and revaccination. Protective titers of antibodies against measles were preserved in 51 people (51.5%), and 48 (48.5%) were seronegative. When assessing immunogenicity on days 14, 45 after the introduction of the vaccine, it turned out that by day 14, 27 out of 53 children (50.9%) developed measles antibodies, and by day 45, 33 out of 53 children (62.3%), the rest of the children did not developed a protective level of antibodies, including 3 of 6 revaccinated. Conclusion. Thus, children with malignant diseases, regardless of the number of previous vaccinations and the duration of the end of therapy, become unprotected or have low titers of antibodies to measles in 83.8%, and immunization after treatment is effective in 62.3% of cases.

Second dose of measles-containing vaccine coverage and associated factors among children aged 24-36 months in Gondar city, Central Gondar, Northwest Ethiopia, 2023.

Measles caused 207,000 deaths worldwide in 2019. Ethiopia ranks among the top 10 countries in the world with the highest number of measles cases. However, the coverage of the second dose of measles-containing vaccine (MCV2) remains low. To increase coverage, the government of Ethiopia launched a nationwide measles vaccination campaign. Despite this intervention, the coverage is still below target, and there is scarce information in the study area. Therefore, this study aimed to assess MCV2 coverage and associated factors among children aged 24-36 months in Gondar city, Central Gondar, Northwest Ethiopia, 2023. A community-based cross-sectional study was conducted among 621 children aged 24-36 months using a systematic random sampling technique from 25 April to 25 May. A pre-tested, interviewer-administered, and structured questionnaire was used and collected using Kobo Toolbox and then transferred to Stata version 17 for further analysis. The binary logistic regression model was used to identify factors, and the presence of an association was declared using a p-value of <0.05. Similarly, an adjusted odds ratio with a 95% confidence interval was used to interpret the direction and strength of an association. A total of 621 children, with a response rate of 98.1%, participated in the study. The coverage of the second dose of MCV was 75.68% (95% CI: 72.1-78.9). The following factors were significantly associated with measles-containing vaccine second dose (MCV2) coverage: father as the household head (AOR: 3.06, 95% CI: 1.43-6.44), first birth order (AOR: 4.45, 95% CI: 1.21-16.3), four and above antenatal care (ANC) follow-ups (AOR: 5.18, 95% CI:1.62-16.5), postnatal care (PNC) service utilization (AOR: 2.57, 95% CI:1.27-5.15), at least two doses of vitamin A uptake (AOR: 6.39, 95% CI: 2.67-15.2), mothers having high awareness (AOR: 1.97, 95% CI:1.15-3.4), and good perception (AOR: 3.6, 95% CI: 2-6.47) about measles vaccination. The coverage of MCV2 in the study area is lower than the national and global target of above 95%. Head of household, birth order, ANC follow-up, PNC service utilization, vitamin A uptake, awareness, and perception of mothers about measles vaccination were significant factors for MCV2 coverage. Creating awareness, increasing the perception of mothers about measles vaccination, and strengthening the ANC and PNC services will increase the coverage.

Measles outbreak investigation in Berhet District, North Shewa, Ethiopia.

Measles, though usually self-limiting, can have severe consequences influenced by factors such as vaccination and nutrition, notably vitamin A deficiency and malnutrition. Despite progress, contextual changes and implementation issues have hampered efforts, resulting in increased outbreaks and cases of measles. This study seeks to pinpoint outbreak features, risk factors, and strategies for preventing and controlling measles. A descriptive cross-sectional study and a 1:2 unmatched case-control study design were employed. All 101 suspected measles cases listed on the line-list were included in the descriptive research, with 60 measles patients and 120 controls included in the case-control investigation. Line-list data were cleaned and analyzed using a pivot table in Microsoft Excel 2016. Subsequently, the data were cleaned, entered into Epi Info 7.2, and exported to SPSS 26 for analysis. Twenty cases occurred per 10,000 individuals. Men accounted for 67.3% of cases, with ages ranging from 5 months to 45 years and mean and standard deviations of 9.6 and 7.6, respectively. Age group of 5-14 years comprised 57.4% of cases, followed by 1-4 years with 24.8%. Being unvaccinated against measles showed an adjusted odds ratio (AOR) of 12.06 (95% CI: 3.12-46.52). Travel history to regions with active cases had an AOR of 5.73 (95% CI: 1.78-18.38). Contact with a measles patient showed an AOR of 10.3 (95% CI: 3.48-30.5). Understanding the measles transmission mechanism had an AOR of 0.164 (95% CI: 0.049-0.55), and awareness of the disease's preventability had an AOR of 0.233 (95% CI: 0.67-0.811). All factors were independently associated with the illness. This outbreak affected a broader age range with a high attack rate, mainly in the age group of 5-14-years. Over 35% of cases lacked measles vaccination, indicating low administrative vaccine coverage. Factors contributing to the outbreak include lack of measles vaccination, travel to areas with active disease, contact with cases, and insufficient knowledge of measles transmission and prevention strategies among mothers and caregivers.

Mechanistic insights into immune amnesia and immunity induced by measles infection and vaccination via comprehensive antiviral antibodies profiling

Abstract Measles is a disease known to induce acute immune amnesia and immunosuppression with increased susceptibility to other infections, while paradoxically conferring patients with life-long immunity to measles. However, it is not clear if the live-attenuated measles vaccine (LAMV) induces immunosuppression comparable to the wild-type measles (WT MeV) infection, nor how mechanistically LAMV and WT MeV affect antibodies specific to different pathogens. Therefore, we utilized VirScan, a phage-display immunoprecipitation and sequencing (PhIP-seq) technology for virome-wide detection of antibodies against viral epitopes, to compare longitudinal antibody diversity in plasma samples from WT MeV and LAMV-infected rhesus macaques (RMs) (n=10 and 6 respectively, with 5 longitudinal timepoints at D0, D14/15, D28, D84/89, D112/168/176). Preliminary analysis showed that WT MeV led to more long-term depletion of pre-existing antibodies to various viral peptides, while mounting a MeV-specific antibody response with greater intensity and breadth than LAMV-infected RM. Furthermore, in our sex difference analysis, male RMs elicited a stronger MeV response than female, particularly to N protein; also a more polyclonal MeV humoral response In summary, our work provided crucial mechanistic insights into immune amnesia and immunity induced by natural infection versus vaccination, highlighting the public health value of the measles vaccine in averting MeV-induced immune amnesia.

Determinants of second-dose measles vaccination dropout in Ethiopia: A community-based matched case-control study

BackgroundMeasles vaccination is the most important public health intervention and a cost-effective strategy to reduce morbidity and mortality in under-five children. Although Ethiopia's government developed a measles elimination strategic plan by 2020, the full coverage of immunization was 43 %. Therefore, this study aimed to identify determinants of second-dose measles vaccination (MCV2) dropout among children aged 24–35 months in East Bale Zone, Ethiopia. MethodA community-based matched case-control study was conducted among 351 children (117 cases and 234 controls). Children who received the first dose of measles vaccine but did not receive the second dose were cases, and children who received both doses of measles vaccine were control. The matches were based on age and residence. The data were collected using a structured questionnaire, entered into Epi Data 3.1, cleaned, exported, and analyzed using Stata version 16.1. A multivariable conditional logistic regression analysis was performed. Variables with a P value of <0.05 were considered significant determinants of the dependent variable at the 95 % confidence level. ResultsMothers who were unable to read and write (mAOR: 4.0; 95 % CI: 1.59–10.2), did not receive counseling (mAOR: 3.19; 95 % CI: 1.62–6.27), spent ≥30 min to reach health facilities (mAOR; 2.76, 95 % CI: 1.25–6.1), and did not attend postnatal care (mAOR; 3.46, 95 % CI: 1.58–7.57) were significantly and positively associated with second-dose measles vaccination dropout. In addition, mothers who had poor knowledge of second-dose measles vaccination (mAOR; 3.20, 95 % CI: 1.50–6.70) and waited more than an hour for measles vaccination at health facilities (mAOR; 2.61, 95 % CI: 1.0–6.20) were significantly more likely to experience second-dose measles vaccine dropout. ConclusionsThe key factors associated with second-dose measles vaccination dropout are maternal illiteracy, lack of PNC, inadequate maternal knowledge and poor counseling about MCV2 vaccination, long distances travel to healthcare facilities and extended waiting times at vaccination providing sites. Health extension workers emphasize strengthening home visit programs in catchment households to improve mothers' awareness of measles vaccination.

Shedding of measles vaccine RNA in children after receiving measles, mumps and rubella vaccination

BackgroundMeasles, mumps, and rubella(MMR) vaccination is critical to measles outbreak responses. However, vaccine reactions and detection of measles vaccine RNA in recently immunized persons may complicate case classification especially in those presenting with another respiratory viral illness. We aim to characterize cases of measles vaccine shedding in recently vaccinated children presenting with respiratory viral symptoms. MethodsChildren who were tested with a multiplex respiratory panel <30 days after receiving MMR were identified. Remnant nasopharyngeal(NP) samples were tested for measles vaccine by PCR. Medical records were reviewed for demographics, presenting symptoms, and test results. ResultsFrom January 2022 to March 2023, 127 NP from children who received MMR were tested. Ninety-six NP were collected after the first dose, of which 33(34.4 %) were positive for vaccine RNA. The median interval between MMR and detection was 11.0 days. Thirty-one NP were collected after the second MMR and 1(3.2 %) was positive; time between the vaccination and detection was 18.9 days. Median cycle threshold(Ct) value of the measles PCR for vaccine shedding was significantly higher than median Ct in children with wild-type infection. ConclusionShedding of measles vaccine RNA is not uncommon and vaccine RNA can be detected up to 29 days post MMR; the amount of vaccine RNA shedding is low indicated by high Ct values. Clinicians and public health officials should consider performing measles vaccine testing on those testing positive for measles within one month of MMR vaccination, especially if the Ct value is high and definitive epidemiological links are absent.

B and T cell repertoire and gene expression differences in measles infection and vaccination revealed by longitudinal single-cell RNA/VDJ sequencing

Abstract While wild-type measles virus (WT MeV) was demonstrated to induce immune amnesia, it paradoxically still elicited high titers of measles-specific antibodies longitudinally; and much higher than the live-attenuated measles vaccine (LAMV). In order to further understand the longitudinal B and T repertoires, clonotype evolution and gene expression difference in WT MeV and LAMV, we conducted longitudinal single-cell RNA/VDJ sequencing of peripheral blood mononuclear cells (PBMC) from WT MeV and LAMV-infected rhesus macaques (RMs) (n = 3 in each WT MeV and LAMV groups, with 4 timepoints at D0, D11, D42/56, D168/176). Firstly, B cell subtypes (e.g. naïve, memory, activated and antibody-secreting B cells) were successfully annotated in PBMC based on key gene markers and immunogenetic information. Furthermore, preliminary analysis of 1 WT MeV and 1 LAMV revealed interesting differences in the B cell repertoire, including a more diverse usage of IGHV genes, greater isotype switching from IgD/M to IgGs, higher level of somatic hypermutation and later B cell clonal expansion peak in LAMV than WT-MeV infected RMs longitudinally. Interestingly, there was greater T cell clonotype expansion in the WT MeV than LAMV RMs. Our study highlights the differential humoral and adaptive immune responses between LAMV and WT MeV infections, uncovering important immunogenetic understanding in natural infection and vaccination.

Analysis of Suspected Measles Cases with Discrepant Measles-Specific IgM and rRT-PCR Test Results, Japan.

We investigated clinically suspected measles cases that had discrepant real-time reverse transcription PCR (rRT-PCR) and measles-specific IgM test results to determine diagnoses. We performed rRT-PCR and measles-specific IgM testing on samples from 541 suspected measles cases. Of the 24 IgM-positive and rRT-PCR--negative cases, 20 were among children who received a measles-containing vaccine within the previous 6 months; most had low IgG relative avidity indexes (RAIs). The other 4 cases were among adults who had an unknown previous measles history, unknown vaccination status, and high RAIs. We detected viral nucleic acid for viruses other than measles in 15 (62.5%) of the 24 cases with discrepant rRT-PCR and IgM test results. Measles vaccination, measles history, and contact history should be considered in suspected measles cases with discrepant rRT-PCR and IgM test results. If in doubt, measles IgG avidity and PCR testing for other febrile exanthematous viruses can help confirm or refute the diagnosis.

Raising Epidemiological Awareness: Assessment of Measles/MMR Susceptibility in Highly Vaccinated Clusters within the Hungarian and Croatian Population-A Sero-Surveillance Analysis.

Perceptions of the complete eradication of vaccine-preventable diseases such as measles, mumps, and rubella (MMR) may foster complacency and compromise vaccination efforts. Decreased measles vaccination rates during the COVID-19 pandemic have heightened the risk of outbreaks, even in adequately vaccinated populations. To address this, we have aligned with ECDC recommendations, leveraging previous cross-border sero-epidemiological assessments between Pécs, Hungary, and Osijek, Croatia, to identify latent risk groups and uncover potential parallels between our nations. Testing 2680 Hungarian and 1764 Croatian serum samples for anti-MMR IgG via ELISAs revealed anti-measles seropositivity ratios below expectations in Croatian cohorts aged ~20-30 (75.7%), ~30-40 (77.5%) and ~40-50 years (73.3%). Similarly, Hungarian samples also showed suboptimal seropositivity ratios in the ~30-40 (80.9%) and ~40-50 (87.3%) age groups. Considering mumps- and rubella-associated seropositivity trends, in both examined populations, individuals aged ~30-50 years exhibited the highest vulnerability. Additionally, we noted congruent seropositivity trends across both countries, despite distinct immunization and epidemiological contexts. Therefore, we propose expanding research to encompass the intricate dynamics of vaccination, including waning long-term immunity. This understanding could facilitate targeted interventions and bolster public awareness. Our findings underscore persistent challenges in attaining robust immunity against measles despite vaccination endeavors.

Case Ascertainment of Measles during a Large Outbreak-Laboratory Compared to Epidemiological Confirmation.

Measles is a highly contagious viral disease, and hence, sufficient herd immunity is obligatory to prevent infection transmission. Measles is still a cause of considerable disease burden globally, mainly in children. During a national measles outbreak in Israel in 2018-2019, the peak incidence rates occurred in the Jerusalem district. Most measles cases in the Jerusalem district (75.5%, 1702) were observed in children younger than 15 years of age, 49.2% (1109) were in children under 5 years of age, and 18.9% (425) were in infants under 1 year of age. The routine measles vaccination schedule includes two doses at 1 and 6 years of age. Most cases (1828, 81.1%) were unvaccinated (zero measles vaccine doses). These cases comprised the 425 affected infants under 1 year of age, who were ineligible for vaccination, along with the 1403 children over 1 year of age, who were otherwise unvaccinated. This study aimed to describe the epidemiologic and laboratory features of this measles outbreak, and to investigate case ascertainment (laboratory confirmed compared to epidemiologically confirmed cases). The study population included 2254 measles cases notified during the period spanning June 2018 to May 2019 in the Jerusalem district (incidence rate 176 per 10,000 population). Of the 2254 cases, 716 (31.8%) were laboratory confirmed, and 1538 (68.2%) were confirmed as epidemiologically linked. Most laboratory confirmed cases (420, 58.7%) underwent real-time PCR tests. Serological tests (measles IgM and IgG) were used in 189 (26.4%) cases, and a combination of RT-PCR and serology was used in 107 (14.9%) cases. In a multivariate model analysis, the variables significantly associated (after adjustment) with higher odds for laboratory confirmation included month of disease onset (late), additional measles cases in the household (single case), place of medical treatment (hospital; either emergency department, or hospitalization) and vaccination status (at least one prior vaccine dose). The measles outbreak described demonstrates the urgency of addressing vaccination gaps with appropriate outbreak prevention programs. The road to measles elimination needs to be paved with robust public health infrastructure, excellent field epidemiology for outbreak surveillance, investigation, and control, and laboratory proficiency.

Epidemiological study of the occurrence of measles in children aged 0-15 years in the Banalia Health Zone (DR Congo) during 2022

Introduction: In 2021, the Banalia Health Zone experienced two measles epidemics with a vaccine completeness rate of 69% according to data provided by the Tshopo Provincial Health Division. The aim of the study was to list the epidemiological characteristics of measles cases in the Banalia Health Zone, to determine the incidence of measles in children aged 0-15 years, and to analyze the vaccination status of children with measles. Methodology: This was a retrospective descriptive study, based on the acquisition of data from the medical records of the targeted children or from data registers at the time of submission. A total of 3,968 children with measles were selected from the various health centers and areas of the Banalia Health Zone. Results: We observed that 64.6% of the subjects in the study were aged between 0 and 5 years; 40.77% of measles cases were recorded in September 2022. The measles vaccination rate was 39.19% and the case fatality rate was 2.8%. The Panga 2 axis had the highest number of measles cases, with a prevalence rate of 29.03%. Conclusion: Measles is a major cause of morbidity and mortality in the Banalia Health Zone. The age group most affected is 0-5 years. Vaccination and surveillance systems need to be strengthened to reduce the growing risk posed by measles.