Search Results (350)

Seasonal influenza is an acute respiratory infectious disease due to influenza viruses, causing a relevant number of illnesses and deaths each year worldwide. Influenza is a preventable disease by vaccination. The aim of this study was to assess the epidemiology of seasonal influenza in Italy through the analysis of data from the epidemiological and virological RespiVirNet surveillance system for the season 2010/2011 to 2023/2024 to identify the epidemiological key points to plan the most appropriate vaccination strategies. The cumulative and maximum weekly incidence of influenza-like illness (ILI) and epidemic period (beginning, end, duration in weeks) were assessed in the pre-pandemic period (2010/2011–2019/2020) and they were compared to the pandemic and post-pandemic one. In all seasons, children reported the highest incidence values of ILI and longer epidemic periods in contrast with the older population. The epidemic seasons 2020/2021 and 2021/2022 had abnormal trends while in the last seasons 2022/2023 and 2023/2024 the epidemiological and virological trends of ILI were confirmed as reported in the pre-pandemic period but with high intensity. Influenza virus A was predominant: the H3N2 subtype circulated more than virus H1N1pdm09. In the few seasons when influenza virus B was the most frequent influenza agent, it co-circulated with influenza virus A. The monitoring of cases is the fundamental tool to better understand the epidemiology of influenza and to optimize future preventive strategies. Full article

A strategic priority of the World Health Organization’s Immunization Agenda 2030 is to increase vaccination coverage and equity through reaching “zero-dose” children. Through an ecological study, we sought to quantify the impact of the COVID-19 pandemic on the coverage of the pentavalent and the measles/rubella vaccines in Kenya, without implying causality. The monthly number of doses from January 2017 to August 2022 were obtained from the Kenya Health Information System for the pentavalent and the measles/rubella vaccines. Immediate (step) and long-term (ramp) changes following interruptions occurring during the period from March 2020 to December 2020 were assessed through an interrupted time series analysis using an autoregressive integrated moving average (ARIMA) model, accounting for seasonality. In December 2020, there was an immediate decrease of 8337, 12,212, and 20,848 in the number of doses for the first, second, and third dose of the pentavalent vaccine, respectively (statistically significant for the third dose only). This corresponded to a percentage relative difference of −21.6, −20.1, and −24.5, respectively, for three doses of pentavalent vaccines, while for measles/rubella vaccine it was −27.3 and −33.6, respectively, for the first and second dose. COVID-19 resulted in interruptions affecting routine immunization, but recovery occurred within four months. Full article

More than 100 laboratories in the World Health Organization Global Measles and Rubella Laboratory Network (GMRLN) perform nucleic acid-based methods for case confirmation of measles or rubella infections and/or strain surveillance (genotyping). The quality of laboratory data is critical to ensure that diagnostic results and country reports to regional verification committees are based on accurate data. A molecular External Quality Assurance (mEQA) program was initiated by the US-CDC in 2014 to evaluate the performance of laboratories in the network. The inclusion of testing for measles and rubella viruses, with a focus on detection and genotyping, plus the diversity of assays and platforms employed required a flexible and comprehensive proficiency testing program. A stepwise introduction of new evaluation criteria gradually increased the stringency of the proficiency testing program, while giving laboratories time to implement the required changes. The mEQA program plays an important role in many processes in the GMRLN, including informing plans for the training of laboratory staff, access to reagents, and the submission of sequence data to global databases. The EQA program for Local Public Health Institutes in Japan is described as an example for national mEQA programs. As more laboratories initiate molecular testing, the mEQA will need to continue to expand and to adapt to the changing landscape for molecular testing. Full article

Efforts to control and eliminate measles and rubella are aided by high-quality surveillance data—supported by laboratory confirmation—to guide decision-making on routine immunization strategies and locations for conducting preventive supplementary immunization activities (SIAs) and outbreak response. Important developments in rapid diagnostic tests (RDTs) for measles and rubella present new opportunities for the global measles and rubella surveillance program to greatly improve the ability to rapidly detect and respond to outbreaks. Here, we review the status of RDTs for measles and rubella Immunoglobulin M (IgM) testing, as well as ongoing questions and challenges regarding the operational use and deployment of RDTs as part of global measles and rubella surveillance. Efforts to develop IgM RDTs that can be produced at scale are underway. Once validated RDTs are available, clear information on the benefits, challenges, and costs of their implementation will be critical for shaping deployment guidance and informing country plans for sustainably deploying such tests. The wide availability of RDTs could provide new programmatic options for measles and rubella elimination efforts, potentially enabling improvements and flexibility for testing, surveillance, and vaccination. Full article

Measles threatens the lives and livelihoods of tens of millions of children and there are countries where routine immunization systems miss enough individuals to create the risk of large outbreaks. To help address this threat, measles supplementary immunization activities are time-limited, coordinated campaigns to immunize en masse a target population. Timing campaigns to be concurrent with building outbreak risk is an important consideration, but current programmatic standards focus on campaigns achieving a high coverage of at least 95%. We show that there is a dramatic trade-off between campaign timeliness and coverage. Optimal timing at coverages as low as 50% for areas with weak routine immunization systems is shown to outperform the current standard, which is delayed by as little as 6 months. Measured coverage alone is revealed as a potentially misleading performance metric. Full article

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

Measles is a highly infectious disease leading to high morbidity and mortality impacting people’s lives and economies across the globe. The measles vaccine saves more lives than any other vaccine in the Essential Programme of Immunization and is also the most cost-effective vaccine, with an extremely high return on investment. This makes achieving measles elimination through vaccination a key child health intervention, particularly in low-income countries, where the overwhelming majority of measles deaths continue to occur. All countries and regions of the world have committed to achieving measles elimination, yet many have faced challenges securing political commitment at national and global levels and predictable, timely, and flexible support from global donors, and experienced setbacks during the COVID-19 pandemic. This has happened against a backdrop of stagnant measles vaccination coverage and declining enthusiasm for vertical programmes, culminating in a World Health Organization Strategic Advisory Group of Experts (WHO SAGE) review of the feasibility of measles eradication in 2019. Sustaining the elimination of measles long term is extremely difficult, and some countries have lost or nearly lost their measles elimination status in the face of ongoing importation of cases from neighbouring or closely connected countries in which elimination had been delayed. Thus, a widening equity gap in measles immunisation coverage creates challenges for all countries, not just those facing the greatest burden of measles morbidity and mortality. Delaying elimination of measles in some countries makes it cumulatively harder for all countries to succeed for three principal reasons: increased inequity in measles immunisation coverage makes outbreaks more likely to happen and to be larger; political will is very difficult to sustain; and immunity may wane to a point that transmission is re-established. New strategies are needed to support countries and regions in their vision for a world without measles, including ways to galvanise domestic, regional and global resources and ignite the political will that is essential to make the vision a reality. Full article

This study explores the enhancement of MMR vaccination rates in the deep south of Thailand through a culturally tailored intervention that incorporates storytelling and singing, aligning with local cultural and religious values. The “Anees has Measles” intervention, developed with input from community stakeholders including health workers, religious leaders, and parents, featured traditional melodies in its singing activities. The intervention comprised two main components: storytelling sessions and singing activities, both utilizing culturally resonant content and formats to effectively engage the community. Conducted from December 2019 to March 2020 across eight districts in five provinces, the study targeted children aged 18 months to 5 years in government child care centers. Results indicated a substantial increase in MMR vaccination coverage from 44.3% to 72.0% twelve months post-intervention, and further to 77.0% at 48 months post-intervention, representing a significant and sustained improvement (p < 0.001). This marked and continuous increase demonstrates the effectiveness of culturally adapted health education in areas with significant vaccine hesitancy. The findings highlight the importance of integrating culturally and religiously sensitive methods into public health strategies, significantly enhancing vaccine acceptance and coverage in diverse and conservative settings. This approach suggests a broader applicability for similar interventions in comparable contexts globally. Full article

Passive immunisation with normal human immunoglobulin (NHIG) is recommended as post-exposure prophylaxis (PEP) for higher-risk measles contacts where vaccination is contraindicated. However, the concentration of measles-specific antibodies in NHIG depends on antibody levels within pooled donor plasma. There are concerns that measles immunity in the Australian population may be declining over time and that blood donors’ levels will progressively decrease, impacting levels required to produce effective NHIG for measles PEP. A cross-sectional study of Australian plasmapheresis donors was performed using an age-stratified, random sample of recovered serum specimens, collected between October and November 2019 (n = 1199). Measles-specific IgG antibodies were quantified by ELISA (Enzygnost anti-measles virus IgG, Siemens), and negative and equivocal specimens (n = 149) also underwent plaque reduction neutralisation testing (PRNT). Mean antibody levels (optical density values) progressively decreased from older to younger birth cohorts, from 2.09 [±0.09, 95% CI] to 0.58 [±0.04, 95% CI] in donors born in 1940–1959 and 1990–2001, respectively (p < 0.0001). This study shows that mean measles-specific IgG levels are significantly lower in younger Australian donors. While current NHIG selection policies target older donors, as younger birth cohorts become an increasingly larger proportion of contributing donors, measles-specific antibody concentrations of NHIG will progressively reduce. We therefore recommend monitoring measles-specific antibody levels in future donors and NHIG products in Australia and other countries that eliminated measles before the birth of their youngest blood donors. Full article

Measles is the most contagious communicable disease, causing an estimated 5.5 million cases and more than 30,000 deaths in the Western Pacific Region (WPR) during 2000. Rubella infection in a pregnant woman can be devastating for the foetus, resulting in congenital rubella syndrome (CRS) in 90% of rubella infections in early pregnancy. It was estimated that approximately 9000 CRS cases occurred in the WPR in 2010. World Health Organization (WHO) Member States in the WPR decided in 2003 to eliminate measles and in 2014 to eliminate rubella from the region. While the WPR successfully attained historically low measles incidence in 2012, it experienced a region-wide measles resurgence in 2013–2016. During the regional resurgence, WHO and Member States accumulated greater knowledge on the epidemiology of measles and rubella in the WPR and strategies to maintain gains. The implementation of the resulting new regional strategy and plan of action from 2018 has proven that measles and rubella elimination is achievable and sustainable under the pressure of multiple importations of measles virus during the world-wide measles resurgences in 2018–2019. This article discusses this progress and achievements towards achieving the global eradication of measles and rubella. Full article

Measles and rubella remain global health threats, despite the availability of safe and effective vaccines. Estimates of population immunity are crucial for achieving elimination goals and assessing the impact of vaccination programs, yet conducting well-designed serosurveys can be challenging, especially in resource-limited settings. In this review, we provide a comprehensive assessment of 130 measles and rubella studies published from January 2014 to January 2024. Methodologies and design aspects of serosurveys varied greatly, including sample size, assay type, and population demographics. Most studies utilized enzyme immunoassays for IgG detection. Sample sizes showed diverse sampling methods but favored convenience sampling despite its limitations. Studies spanned 59 countries, predominantly including adults, and revealed disparities in seroprevalence across demographics, regions, and notably among migrants and women. Age-related declines in antibodies were observed, particularly among infants, and correlations between vaccination status and seropositivity varied. We conclude with an outlook on measles and rubella serosurveillance, emphasizing the need for proper survey design and the advantages of standardized, multiplex serology assays. Full article

Measles elimination refers to the interruption of measles virus transmission in a defined geographic area (e.g., country or region) for 12 months or more, and measles eradication refers to the global interruption of measles virus transmission. Measles eradication was first discussed and debated in the late 1960’s shortly after the licensure of measles vaccines. Most experts agree that measles meets criteria for disease eradication, but progress toward national and regional measles elimination has slowed. Several paths to measles eradication can be described, including an incremental path through country-wide and regional measles elimination and phased paths through endgame scenarios and strategies. Infectious disease dynamic modeling can help inform measles elimination and eradication strategies, and all paths would be greatly facilitated by innovative technologies such as microarray patches to improve vaccine access and demand, point-of-contact diagnostic tests to facilitate outbreak responses, and point-of-contact IgG tests to identify susceptible populations. A pragmatic approach to measles eradication would identify and realize the necessary preconditions and clearly articulate various endgame scenarios and strategies to achieve measles eradication with an intensified and coordinated global effort in a specified timeframe, i.e., to “go big and go fast”. To encourage and promote deliberation among a broad array of stakeholders, we provide a brief historical background and key considerations for setting a measles eradication goal. Full article

Vaccination Week in the Americas (VWA) is a yearly regional initiative that promotes the benefits of vaccination to all persons in the region. In its 22-year history, more than 1.15 billion people have been reached under the framework of VWA across more than 40 countries and territories. This review examines multiple PAHO and WHO data points, documents and reports related to measles/rubella vaccination coverage and VWA since its inception. Its goal is to document the impact that the VWA has had in maintaining and accelerating measles and rubella disease elimination, in the context of PAHO’s Disease Elimination Initiative. The results suggest that VWA’s contributions to measles and rubella elimination have been substantial. Every year, VWA promotes (a) renewed political commitment to the immunization program from the highest political authorities of Member States; (b) vaccination operations to close immunity gaps, recover under-vaccinated persons, and reach chronically underserved populations; and (c) the dissemination of messages on the benefits of vaccination through regional and national communications campaigns. VWA will continue to be an important contributor to disease elimination efforts in the Americas, even as new targets are set in response to the evolving epidemiological landscape. Full article

Rubella infection is typically mild or asymptomatic except when infection occurs during pregnancy. Infection in early pregnancy can cause miscarriage, stillbirth, or congenital rubella syndrome. Only individuals that are still susceptible to rubella infection during child-bearing age are vulnerable to this burden. Rubella-containing vaccine (RCV) is safe and effective, providing life-long immunity. However, average age-at-infection increases with increasing vaccination coverage, which could potentially lead to increased disease burden if the absolute risk of infection during child-bearing age increases. The dynamics of rubella transmission were explored using EMOD, a software tool for building stochastic, agent-based infection models. Simulations of pre-vaccine, endemic transmission of rubella virus introduced RCV at varying levels of coverage to determine the expected future trajectories of disease burden. Introducing RCV reduces both rubella virus transmission and disease burden for a period of around 15 years. Increased disease burden is only possible more than a decade post-introduction, and only for contexts with persistently high transmission intensity. Low or declining rubella virus transmission intensity is associated with both greater burden without vaccination and greater burden reduction with vaccination. The risk of resurgent burden due to incomplete vaccination only exists for locations with persistently high infectivity, high connectivity, and high fertility. A trade-off between the risk of a small, future burden increase versus a large, immediate burden decrease strongly favors RCV introduction. Full article

Molecular surveillance of circulating measles variants serves as a line of evidence for the absence of endemic circulation and provides a means to track chains of transmission. Molecular surveillance for measles (genotyping) is based on the sequence of 450 nucleotides at the end of the nucleoprotein coding region (N450) of the measles genome. Genotyping was established in 1998 and, with over 50,000 sequence submissions to the Measles Nucleotide Surveillance database, has proven to be an effective resource for countries attempting to trace pathways of transmission. This review summarizes the tools used for the molecular surveillance of measles and describes the challenge posed by the decreased number of circulating measles genotypes. The Global Measles and Rubella Laboratory Network addressed this challenge through the development of new tools such as named strains and distinct sequence identifiers that analyze the diversity within the currently circulating genotypes. The advantages and limitations of these approaches are discussed, together with the need to generate additional sequence data including whole genome sequences to ensure the continued utility of strain surveillance for measles. Full article