[Effects of the vaccination campaign on hospitalization and mortality linked to measles in Brazil in the last decade]. / Efeitos da campanha de vacinação nas internações e mortalidade relacionados ao sarampo no Brasil na última década.

Measles is one of the main causes of morbidity and mortality in the pediatric population and it can be prevented with 100% effectiveness by vaccination. However, the disease remains active in throughout Brazil. The scope of this article is to evaluate the population's adherence to vaccination and the potential connection with hospitalizations and mortality in relation to measles in Brazil. This is an ecological study based on secondary data on mortality and hospitalizations due to measles and vaccination coverage against the disease in Brazil from 2013 to 2022. The peak of adherence to the measles vaccination schedule occurred in the 3 years that preceded the eradication of the disease in the country, which occurred in 2016. In this interval, there are the lowest hospitalization rates, with zero mortality from 2014 to 2017. On the other hand, there has been a marked drop in vaccination rates since 2019, when the disease resurfaced in Brazil. Concomitantly, hospitalization and mortality rates reach the highest recorded values. Population adherence to the complete measles vaccination schedule, which is essential to control the disease and related deaths, is insufficient, which is reflected in hospitalization and mortality rates.

O sarampo é uma das principais causas de morbidade e mortalidade na população pediátrica e pode ser prevenido com 100% de eficácia pela vacinação. No entanto, a doença permanece ativa no território brasileiro. O objetivo do artigo é avaliar a adesão da população à vacinação e a possível relação com hospitalização e mortalidade em relação ao sarampo no Brasil. Trata-se de um estudo ecológico realizado a partir de dados secundários de mortalidade e internações acerca do sarampo e da cobertura vacinal contra a doença no Brasil nos anos de 2013 a 2022. O ápice de adesão ao calendário vacinal contra o sarampo se deu nos três anos que precederam a erradicação da doença no país, ocorrida em 2016. Nesse intervalo, tem-se as menores taxas de internação, com a mortalidade zerada de 2014 a 2017. Em contrapartida, verifica-se, desde então, queda na taxas de vacinação, acentuadas a partir de 2019, quando a doença reaparece no Brasil. Concomitantemente, as taxas de internação e mortalidade atingem os valores mais altos registrados. A adesão populacional ao calendário vacinal completo contra o sarampo, essencial ao controle da doença e dos óbitos relacionados, está insuficiente, o que se reflete nas taxas de internações e mortalidade.

Measles Vaccine Coverage and Disease Outbreaks: A Systematic Review of the Early Impact of COVID-19 in Low and Lower-Middle Income Countries.

Objectives: We aimed to evaluate changes to measles-containing vaccine (MCV) provision and subsequent measles disease cases in low- and lower-middle income countries (LICs, LMICs) in relation to the COVID-19 pandemic. Methods: A systematic search was conducted of MEDLINE, OVID EMBASE and PubMed records. Primary quantitative and qualitative research studies published from January 2020 were included if they reported on COVID-19 impact on MCV provision and/or measles outbreak rates within LICs and LMICs. Results: 45 studies were included. The change in MCV1 vaccination coverage in national and international regions ranged -13% to +44.4% from pre-COVID time periods. In local regions, the median MCV1 and overall EPI rate changed by -23.3% and -28.5% respectively. Median MCV2 rate was disproportionally impacted in local areas during COVID-interruption time-periods (-48.2%) with ongoing disruption in early-recovery time-periods (-17.7%). 8.9% of studies reported on vaccination status of confirmed measles cases; from these, 71%-91% had received no MCV dose. Conclusion: MCV vaccination coverage experienced ongoing disruption during the recovery periods after initial COVID-19 disruption. Vaccination in local area datasets notably experienced longer-term disruption compared to nationally reported figures.

Effect of postpartum family planning intervention and associated factors during child immunization in Addis Ababa, Ethiopia.

Introduction: World Health Organization (WHO) recommends postpartum family planning (PPFP) as a critical component of health care that has the potential to save millions of maternal and infant lives in low- and middle-income countries. Methods: participants in our randomized, controlled trial were mothers coming for vaccination of their child in three selected health centers in Addis Ababa during the first 10 weeks postpartum. Eligible mothers were randomly assigned to intervention (pamphlet-supported counseling about the benefits of family planning) and non-intervention (routine care) arms. Data were collected when mothers came with their infants for a routine measles vaccination at nine months of life. Family planning (FP) use was compared between the groups using logistic regression, and bivariate and multivariate analyses. The study also used Kaplan Meier and Cox regressions to compare the median time of PPFP use and its correlation using SPSS version 26. The research was undertaken from December 2019 to June 2021. Results: a total of 347 women (177 control, 170 intervention) enrolled in the study. Fifty-eight percent were 24-30 years old. Young age, knowledge about FP, previous use of an FP method, and being married were found to be independent predictors for PPFP use. When comparing intervention and non-intervention groups, there was no significant effect on contraceptive use (adjusted OR 0.633 [95% CI 0.385-1.040]). Conclusion: pamphlet-supported counseling of mothers in the first 10 weeks postpartum did not increase PPFP at nine months postpartum. Successful interventions will likely require holistic strategies, especially in resource-limited settings. The trial had been registered with clinicaltrials.gov (NCT04521517) on September 24, 2019.

Coverage and determinants of second-dose measles vaccination among under-five children in East Africa countries: a systematic review and meta-analysis.

Background: One of the biggest breakthroughs of contemporary medicine is measles vaccination. It is essential for the total elimination of measles. Understanding the magnitude and determinants of effective second-dose measles vaccination coverage is a critical task. Accordingly, we set out to check the best available evidence of the pooled second-dose measles vaccination coverage among under-five children in East Africa. Method: We searched electronic databases such as PubMed, Google Scholar, Cochrane, and others. Two reviewers separately carried out the search of the Joanna Briggs Institute, selection of studies, critical appraisal, and data extraction. A third party was involved in resolving the disagreement among the reviewers. Seven studies included in this study, four from Ethiopia, two from Kenya, and one from Tanzania were cross-sectional and published in English language, with publication dates before 29 November 2023. Articles lacking full-text, the intended outcome, and that are not qualitative studies were excluded from the analysis. The Microsoft Excel checklist was used to extract the data and then exported to STATA 11. In addition, I2, Funnel plots, and Egger's test were employed to measure heterogeneity and detect publication bias, respectively. A random effect model was used. Result: The meta-analysis includes a total sample size of 4,962 children from seven articles. The pooled prevalence of second-dose measles vaccination among under-five children in East Africa was found to be 32.22% [95% CI; (18.82, 45.63)], and the significant factors were as follows: birth order (1.72; OR = 95% CI: 1.32, 2.23), information about measles-containing second-dose vaccine (MCV 2) (7.39; OR = 95% CI: 5.21, 10.50), mother's marital status (1.47; OR = 95% CI: 1.05, 2.07), complete immunization for other vaccines (2.17; OR = 95% CI: 1.49, 3.17), and distance of vaccination site (3.31; OR = 95% CI: 2.42, 4.53). Conclusion: The current study found that pooled prevalence of second-dose measles vaccination coverage among under-five children was still very low. It was also observed that birth order, distance of the vaccination site, complete immunization for other vaccines, mother's marital status, and information about MCV were factors associated with second-dose measles vaccination. These factors imply that there is a need for countries and their partners to act urgently to secure political commitment, expand primary health service and health education, and increase vaccination coverage.

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.

Measles second dose vaccine uptake and its associated factors among children aged 24-35 months in Northwest Ethiopia, 2022.

Measles is a major public health problem in under-five children, leading to lifelong complications. Therefore, the study aimed to assess the magnitude of measles second-dose vaccine uptake and its determinants among children aged 24-35 months in Northwest Ethiopia. A community-based cross-sectional study was conducted among 418 children aged 24-35 months in Northwest Ethiopia between January 2022 and February 2022. A simple random sampling technique was used to access study subjects. A binary logistic regression model was employed. An adjusted odd ratio with a 95% confidence interval (CI) and a p-value < 0.05 was used to declare significant predictors of measles second dose vaccine uptake. The magnitude of the measles second dose vaccine uptake among children aged 24-35 months was 41.39%. Postnatal care visits (AOR: 4.78, CI 1.49, 15.34), child vaccination status of other scheduled vaccines (AOR: 3.88, CI 2.23, 6.73), awareness of the measles second dose vaccine and its schedule (AOR: 8.924, CI 5.27, 15.09), and distance from the vaccination center (AOR: 0.21, CI 0.06, 0.77) were significantly associated with measles second dose vaccine uptake. The uptake of measles second dose vaccine in the study area was low. Therefore, health workers and other partners should initiate awareness creation programs for mothers/caretaker to improve the uptake of measles second dose vaccine.

Measles outbreak investigation in Tocha district, southwestern Ethiopia: an unmatched case-control study.

Background: Measles continues to be a public health challenge in Ethiopia. Rumors of suspected measles were notified on April 8, 2023 from Tocha district. We conducted an assessment to describe measles outbreak and determine risk factors for measles infection in the Tocha district of the Dawuro zone, Southwest Ethiopia. Methods: We conducted a 1:2 unmatched case-control studies from April to May 2023. We took all 147 cases registered on line list for descriptive analyses. We used a total of 74 randomly selected cases and 147 controls for case-control part. Any person in Tocha district with laboratory-confirmed measles IgM antibody; or any suspected person epidemiologically linked to confirmed measles cases from March 23 to April 26 2023, were included in the case. Neighborhood who did not fulfill this standard case definition were included in controls. Data were collected using standardized questionnaires deployed on Kobo Collect. Descriptive analyses were conducted using Epi info version 7.2.5.0. The analyses were performed using Statistical Package for Social Science (SPSS) version 26. Binary logistic regression analyses were utilized to select candidate variables. We conducted multiple logistic regression analysis to identify determinants of measles infection at a p value ≤0.05 with 95% confidence interval. Results: The overall attack rate of 22.64/10,000 for general population and 104.59/10,000 among under-five children were attributed to the outbreak with a case fatality rate of 2.72%. Vaccine coverage in the last year and this year were 73.52 and 53.88%, respectively, while vaccine effectiveness in the district was 79%. Poor house ventilation (AOR = 3.540, 95% CI: 1.663-7.535) and having contact history with the case (AOR = 2.528, 95% CI: 1.180-4.557) were positively related to measles infection while being previously vaccinated for measles (AOR = 0.209, 95% CI: 0.180-4.577) reduce risk of measles infections. Conclusion: The highest attack rate was observed among children under 5 years of age, with a case fatality rate of 2.72%. Vaccination coverage was less than what expected to develop herd immunity. Strategies to increase vaccination coverage and strengthening surveillance systems for rumor identification and early responses to prevent person to person transmission are recommended.

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

Introduction: 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. Methods: 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. Results: 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. Conclusion: 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.

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

Background: 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. Methods: 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. Results: 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. Conclusion and recommendations: 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.

A measles and rubella vaccine microneedle patch in The Gambia: a phase 1/2, double-blind, double-dummy, randomised, active-controlled, age de-escalation trial.

BACKGROUND: Microneedle patches (MNPs) have been ranked as the highest global priority innovation for overcoming immunisation barriers in low-income and middle-income countries. This trial aimed to provide the first data on the tolerability, safety, and immunogenicity of a measles and rubella vaccine (MRV)-MNP in children. METHODS: This single-centre, phase 1/2, double-blind, double-dummy, randomised, active-controlled, age de-escalation trial was conducted in The Gambia. To be eligible, all participants had to be healthy according to prespecified criteria, aged 18-40 years for the adult cohort, 15-18 months for toddlers, or 9-10 months for infants, and to be available for visits throughout the follow-up period. The three age cohorts were randomly assigned in a 2:1 ratio (adults) or 1:1 ratio (toddlers and infants) to receive either an MRV-MNP (Micron Biomedical, Atlanta, GA, USA) and a placebo (0·9% sodium chloride) subcutaneous injection, or a placebo-MNP and an MRV subcutaneous injection (MRV-SC; Serum Institute of India, Pune, India). Unmasked staff ransomly assigned the participants using an online application, and they prepared visually identical preparations of the MRV-MNP or placebo-MNP and MRV-SC or placebo-SC, but were not involved in collecting endpoint data. Staff administering the study interventions, participants, parents, and study staff assessing trial endpoints were masked to treatment allocation. The safety population consists of all vaccinated participants, and analysis was conducted according to route of MRV administration, irrespective of subsequent protocol deviations. The immunogenicity population consisted of all vaccinated participants who had a baseline and day 42 visit result available, and who had no protocol deviations considered to substantially affect the immunogenicity endpoints. Solicited local and systemic adverse events were collected for 14 days following vaccination. Unsolicited adverse events were collected to day 180. Age de-escalation between cohorts was based on the review of the safety data to day 14 by an independent data monitoring committee. Serum neutralising antibodies to measles and rubella were measured at baseline, day 42, and day 180. Analysis was descriptive and included safety events, seroprotection and seroconversion rates, and geometric mean antibody concentrations. The trial was registered with the Pan African Clinical Trials Registry PACTR202008836432905, and is complete. FINDINGS: Recruitment took place between May 18, 2021, and May 27, 2022. 45 adults, 120 toddlers, and 120 infants were randomly allocated and vaccinated. There were no safety concerns in the first 14 days following vaccination in either adults or toddlers, and age de-escalation proceeded accordingly. In infants, 93% (52/56; 95% CI 83·0-97·2) seroconverted to measles and 100% (58/58; 93·8-100) seroconverted to rubella following MRV-MNP administration, while 90% (52/58; 79·2-95·2) and 100% (59/59; 93·9-100) seroconverted to measles and rubella respectively, following MRV-SC. Induration at the MRV-MNP application site was the most frequent local reaction occurring in 46 (77%) of 60 toddlers and 39 (65%) of 60 infants. Related unsolicited adverse events, most commonly discolouration at the application site, were reported in 35 (58%) of 60 toddlers and 57 (95%) of 60 infants that had received the MRV-MNP. All local reactions were mild. There were no related severe or serious adverse events. INTERPRETATION: The safety and immunogenicity data support the accelerated development of the MRV-MNP. FUNDING: Bill & Melinda Gates Foundation.

Vaccine coverage among children born to immigrant parents in Norway, 2000-2020.

BACKGROUND: The Norwegian Childhood Immunization Program maintains a high national coverage of 95-97% in the most recent years. Whether there are subgroups with lower uptake is less studied. This study examines pertussis and measles vaccination coverage among six immigrant groups in Norway. These vaccines are normally administered as part of different combination vaccines and their coverage rate indicate the national vaccination coverage against a range of additional infections. METHODS: Data from the Norwegian National Population Register were linked at individual level with vaccination data from the Norwegian Immunisation Registry. The final sample consisted of 53,052 children born during 2000-2018 in Norway to parents who were born in Iraq, Lithuania, Pakistan, Poland, Somalia, or Vietnam. Vaccination coverage was measured at 2-years of age. Multivariate linear regression was utilized to estimate the relationship between vaccinations status, year of birth, gender, mother's length of residency in Norway, and area of residence. RESULTS: At two years of age, the majority of the children were vaccinated. Coverage among the groups varied at, above, and below the national average for the two vaccines. For most of the years examined, children born by parents from Lithuania, Poland, and Somalia had lower coverage for the measles vaccine (range 81-84% in 2020) than the national level (97% in 2020). Children born by parents from the Eastern-European countries also had lower coverage than the national level for the pertussis vaccine (range 87-89% in 2020). DISCUSSION: This study illustrates how subgroups with lower vaccination coverage may exists within a well-established vaccination program with high national coverages. Differences in coverage were found for both vaccines, but the differences were more pronounced for the measles vaccine. The high vaccination coverage in Norway provides indirect protection through herd immunity for unvaccinated individuals, however, the lower vaccination coverage in some immigrant groups is a concern.

Increased reports of measles in the Metropolitan City of Milan, northern Italy, September 2023 to March 2024.

Since late 2023, the Metropolitan City of Milan and surrounding areas (northern Italy) have been experiencing a resurgence of measles, with most cases detected starting from January 2024. During this brief period, we observed measles in travellers from endemic areas, participants in international events, vaccinees and healthcare workers. Indigenous cases have also been identified. Even though we have not yet identified large and disruptive outbreaks, strengthening surveillance and vaccination activities is pivotal to help limit the impact of measles spread.

A real-world study on the changing characteristics of measles antibodies in premature infants in China.

The waning of maternal antibodies may cause infants to lose protection against measles before receiving measles-containing vaccine (MCV). The aim of this study is to investigate the changing characteristics and influencing factors of measles antibodies in preterm infants (PT), and to provide scientific basis for optimizing MCV vaccination strategy of the target population. Blood samples were collected from PT and full-term infants (FT) at the chronological age (CA) of 3, 6, and 12 months. Measles antibodies were quantitatively detected by enzyme-linked immunosorbent assay. Demographic and vaccination information were both collected. Kruskal-Wallis rank sum test was used to compare the measles antibodies among different gestation age (GA) groups, and multiple linear regression was performed to identify the correlative factors for the antibodies. Measles antibodies of PT decreased significantly with age increasing before MCV vaccination. The positive rates of antibodies of PT were 10.80% and 3.30% at the age of 3 and 6 months, respectively (p < .001). At 12 months, the measles antibodies and seropositive rate in the infants who received MCV vaccination increased sharply (p < .001). Regression analyzes showed that the younger the GA or the older the age, the lower the antibodies at 3 months(p < .001，p = .018); while the lower measles antibody levels at 3 months and older age predicted the lower antibodies at 6 months(p < .001, p = .029). PT were susceptible to measles due to the low level of maternally derived antibodies before MCV vaccination. More efforts should be considered to protect the vulnerable population during their early postnatal life.

Impact of nutritional status on vaccine-induced immunity in children living in South Africa: Investigating the B-cell repertoire and metabolic hormones.

OBJECTIVES: We explored the role of metabolic hormones and the B-cell repertoire in the association between nutritional status and vaccine responses. METHODS: In this prospective cohort study, nested within a larger randomized open-label trial, 211 South African children received two doses of measles vaccine and two or three doses of pneumococcal conjugate vaccine (PCV). Metabolic markers (leptin, ghrelin and adiponectin) and distribution of B-cell subsets (n = 106) were assessed at 18 months of age. RESULTS: Children with a weight-for-height z-score (WHZ) ≤ -1 standard deviation (SD) at booster vaccination had a decreased mean serotype-specific PCV IgG response compared with those with WHZ > -1 and <+1 SD or WHZ ≥ +1 SD at 9 months post-booster (18 months of age). (Naive) pre-germinal center B-cells were associated with pneumococcal antibody decay between one to nine months post-booster. Predictive performance of elastic net models for the combined effect of B-cell subsets, metabolic hormones and nutritional status (in addition to age, sex, and randomization group) on measles and PCV vaccine response had an average area under the receiver operating curve of 0.9 and 0.7, respectively. CONCLUSIONS: The combined effect of B-cell subsets, metabolic hormones and nutritional status correlated well with the vaccination response for measles and most PCV serotypes. CLINICALTRIALS: gov registration of parent studies: NCT02943902 and NCT03330171.

A measles-vectored vaccine candidate expressing prefusion-stabilized SARS-CoV-2 spike protein brought to phase I/II clinical trials: candidate selection in a preclinical murine model.

In the early COVID-19 pandemic with urgent need for countermeasures, we aimed at developing a replicating viral vaccine using the highly efficacious measles vaccine as vector, a promising technology with prior clinical proof of concept. Building on our successful pre-clinical development of a measles virus (MV)-based vaccine candidate against the related SARS-CoV, we evaluated several recombinant MV expressing codon-optimized SARS-CoV-2 spike glycoprotein. Candidate V591 expressing a prefusion-stabilized spike through introduction of two proline residues in HR1 hinge loop, together with deleted S1/S2 furin cleavage site and additional inactivation of the endoplasmic reticulum retrieval signal, was the most potent in eliciting neutralizing antibodies in mice. After single immunization, V591 induced similar neutralization titers as observed in sera of convalescent patients. The cellular immune response was confirmed to be Th1 skewed. V591 conferred long-lasting protection against SARS-CoV-2 challenge in a murine model with marked decrease in viral RNA load, absence of detectable infectious virus loads, and reduced lesions in the lungs. V591 was furthermore efficacious in an established non-human primate model of disease (see companion article [S. Nambulli, N. Escriou, L. J. Rennick, M. J. Demers, N. L. Tilston-Lunel et al., J Virol 98:e01762-23, 2024, https://doi.org/10.1128/jvi.01762-23]). Thus, V591 was taken forward into phase I/II clinical trials in August 2020. Unexpected low immunogenicity in humans (O. Launay, C. Artaud, M. Lachâtre, M. Ait-Ahmed, J. Klein et al., eBioMedicine 75:103810, 2022, https://doi.org/10.1016/j.ebiom.2021.103810) revealed that the underlying mechanisms for resistance or sensitivity to pre-existing anti-measles immunity are not yet understood. Different hypotheses are discussed here, which will be important to investigate for further development of the measles-vectored vaccine platform.IMPORTANCESARS-CoV-2 emerged at the end of 2019 and rapidly spread worldwide causing the COVID-19 pandemic that urgently called for vaccines. We developed a vaccine candidate using the highly efficacious measles vaccine as vector, a technology which has proved highly promising in clinical trials for other pathogens. We report here and in the companion article by Nambulli et al. (J Virol 98:e01762-23, 2024, https://doi.org/10.1128/jvi.01762-23) the design, selection, and preclinical efficacy of the V591 vaccine candidate that was moved into clinical development in August 2020, 7 months after the identification of SARS-CoV-2 in Wuhan. These unique in-human trials of a measles vector-based COVID-19 vaccine revealed insufficient immunogenicity, which may be the consequence of previous exposure to the pediatric measles vaccine. The three studies together in mice, primates, and humans provide a unique insight into the measles-vectored vaccine platform, raising potential limitations of surrogate preclinical models and calling for further refinement of the platform.

Measles outbreak in the adult age group: Clinical, laboratory, and epidemiological features of the 11 patients admitted to the hospital.

The measles virus, also known as the morbillivirus, or MV, is a virus that infects humans. The goal of this research is to assess to adult cases of measles. Eleven patients thought to be confirmed cases of measles were enrolled in the investigation. Following the identification of symptoms of tiredness, fever, and rash in one soldier, the results of 10 more troops from the pertinent military group were assessed. The diagnosis was made based on the presence of serum immunoglobulin M (IgM) and positive polymerase chain reaction (PCR) results. When the control IgM, immunoglobulin G, and PCR findings were evaluated a fortnight after hospitalization, a cluster of 11 incidents was found. It is now necessary to address the issue of the cautious stance towards vaccination or the anti-vaccination sentiment that has grown increasingly popular, particularly in light of the COVID-19 pandemic, for both our nation and the entire world.