Measles Mortality Research Articles

The Problem with Delaying Measles Elimination.

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.

Evolution and Contribution of a Global Partnership against Measles and Rubella, 2001-2023.

This article describes the arc of global measles and rubella elimination since 2000 from the perspective of the founding partners of the Measles Initiative. The Measles Initiative was formed in 2001 as a partnership among the American Red Cross, the Centers for Disease Control and Prevention, UNICEF, the United Nations Foundation, and the World Health Organization with the aim to reduce measles deaths in low-income countries. Recognizing rubella as the leading infectious disease cause of congenital abnormalities globally and achievement of measles and rubella elimination in the region of the Americas, the partnership was renamed the Measles and Rubella Initiative (MRI) in 2012. The goals of the MRI were at least a 95% reduction in global measles mortality and elimination of measles and rubella in at least five of the six WHO regions. In January 2023, the membership of the partnership was expanded to include the Bill and Melinda Gates Foundation (BMGF) and Gavi the Vaccine Alliance, and its name changed to the IA2030 Measles and Rubella Partnership. We describe the role the partnership has had in measles partner effectiveness and its impact on measles and rubella disease burden, including how the partnership has strategically adapted to the evolving immunization landscape. We conclude with lessons learned regarding the role global partnerships can play in furthering the impact of disease control programs within the current global immunization environment.

Population-Level Risk Factors Related to Measles Case Fatality: A Conceptual Framework Based on Expert Consultation and Literature Review.

A better understanding of population-level factors related to measles case fatality is needed to estimate measles mortality burden and impact of interventions such as vaccination. This study aimed to develop a conceptual framework of mechanisms associated with measles case fatality ratios (CFRs) and assess the scope of evidence available for related indicators. Using expert consultation, we developed a conceptual framework of mechanisms associated with measles CFR and identified population-level indicators potentially associated with each mechanism. We conducted a literature review by searching PubMed on 31 October 2021 to determine the scope of evidence for the expert-identified indicators. Studies were included if they contained evidence of an association between an indicator and CFR and were excluded if they were from non-human studies or reported non-original data. Included studies were assessed for study quality. Expert consultation identified five mechanisms in a conceptual framework of factors related to measles CFR. We identified 3772 studies for review and found 49 studies showing at least one significant association with CFR for 15 indicators (average household size, educational attainment, first- and second-dose coverage of measles-containing vaccine, human immunodeficiency virus prevalence, level of health care available, stunting prevalence, surrounding conflict, travel time to major city or settlement, travel time to nearest health care facility, under-five mortality rate, underweight prevalence, vitamin A deficiency prevalence, vitamin A treatment, and general malnutrition) and only non-significant associations for five indicators (antibiotic use for measles-related pneumonia, malaria prevalence, percent living in urban settings, pneumococcal conjugate vaccination coverage, vitamin A supplementation). Our study used expert consultation and a literature review to provide additional insights and a summary of the available evidence of these underlying mechanisms and indicators that could inform future measles CFR estimations.

Outbreak of measles: threatening India’s goal to achieve elimination

Outbreak of measles: threatening India’s goal to achieve elimination

Analysis of the different interventions scenario for programmatic measles control in Bangladesh: A modelling study.

In recent years measles has been one of the most critical public health problem in Bangladesh. Although the Ministry of Health in Bangladesh employs a broad extension of measles control policies, logistical challenges exist, and there is significant doubt regarding the disease burden. Mathematical modelling of measles is considered one of the most effective ways to understand infection transmission and estimate parameters in different countries, such as Bangladesh. In this study, a mathematical modelling framework is presented to explore the dynamics of measles in Bangladesh. We calibrated the model using cumulative measles incidence data from 2000 to 2019. Also, we performed a sensitivity analysis of the model parameters and found that the contact rate had the most significant influence on the basic reproduction number R0. Four hypothetical intervention scenarios were developed and simulated for the period from 2020 to 2035. The results show that the scenario which combines enhanced treatment for exposed and infected population, first and second doses of vaccine is the most effective at rapidly reducing the total number of measles incidence and mortality in Bangladesh. Our findings also suggest that strategies that focus on a single interventions do not dramatically affect the decline in measles incidence cases; instead, those that combine two or more interventions simultaneously are the most effective in decreasing the burden of measles incidence and mortality. In addition, we also evaluated the cost-effectiveness of varying combinations of three basic control strategies including distancing, vaccination and treatment, all within the optimal control framework. Our finding suggested that combines distancing, vaccination and treatment control strategy is the most cost-effective for reducing the burden of measles in Bangladesh. Other strategies can be comprised to measles depending on the availability of funds and policymakers' choices.

Estimating national-level measles case–fatality ratios in low-income and middle-income countries: an updated systematic review and modelling study

To understand the current measles mortality burden, and to mitigate the future burden, it is crucial to have robust estimates of measles case fatalities. Estimates of measles case-fatality ratios (CFRs) that are specific to age, location, and time are essential to capture variations in underlying population-level factors, such as vaccination coverage and measles incidence, which contribute to increases or decreases in CFRs. In this study, we updated estimates of measles CFRs by expanding upon previous systematic reviews and implementing a meta-regression model. Our objective was to use all information available to estimate measles CFRs in low-income and middle-income countries (LMICs) by country, age, and year. For this systematic review and meta-regression modelling study, we searched PubMed on Dec 31, 2020 for all available primary data published from Jan 1, 1980 to Dec 31, 2020, on measles cases and fatalities occurring up to Dec 31, 2019 in LMICs. We included studies that previous systematic reviews had included or which contained primary data on measles cases and deaths from hospital-based, community-based, or surveillance-based reports, including outbreak investigations. We excluded studies that were not in humans, or reported only data that were only non-primary, or on restricted populations (eg, people living with HIV), or on long-term measles mortality (eg, death from subacute sclerosing panencephalitis), and studies that did not include country-level data or relevant information on measles cases and deaths, or were for a high-income country. We extracted summary data on measles cases and measles deaths from studies that fitted our inclusion and exclusion criteria. Using these data and a suite of covariates related to measles CFRs, we implemented a Bayesian meta-regression model to produce estimates of measles CFRs from 1990 to 2019 by location and age group. This study was not registered with PROSPERO or otherwise. We identified 2705 records, of which 208 sources contained information on both measles cases and measles deaths in LMICS and were included in the review. Between 1990 and 2019, CFRs substantially decreased in both community-based and hospital-based settings, with consistent patterns across age groups. For people aged 0-34 years, we estimated a mean CFR for 2019 of 1·32% (95% uncertainty interval [UI] 1·28-1·36) among community-based settings and 5·35% (5·08-5·64) among hospital-based settings. We estimated the 2019 CFR in community-based settings to be 3·03% (UI 2·89-3·16) for those younger than 1 year, 1·63% (1·58-1·68) for age 1-4 years, 0·84% (0·80-0·87) for age 5-9 years, and 0·67% (0·64-0·70) for age 10-14 years. Although CFRs have declined between 1990 and 2019, there are still large heterogeneities across locations and ages. One limitation of this systematic review is that we were unable to assess measles CFR among particular populations, such as refugees and internally displaced people. Our updated methodological framework and estimates could be used to evaluate the effect of measles control and vaccination programmes on reducing the preventable measles mortality burden. Bill & Melinda Gates Foundation; Gavi, the Vaccine Alliance; and the US National Institutes of Health.

Exacerbation of measles mortality by vaccine hesitancy worldwide

Exacerbation of measles mortality by vaccine hesitancy worldwide

Pakistan at the precipice: The looming threat of measles amidst the COVID-19 pandemic.

The global focus on curbing the COVID-19 pandemic has reduced the overall immunization rates worldwide. This, coupled with increasing malnutrition and strained healthcare, has increased measles cases and mortality globally. Many countries are thus facing outbreaks, with Afghanistan having reported 372 deaths between January and September 2022. Therefore, Pakistan, a country in a similar economic state and the world's fourth highest reported measles cases in 2022, must take action. Moreover, the current flooded state of Pakistan and the subsequent mass movement of population, deterioration of health services, and worsened living conditions all contribute to put the country at a high risk of potentially devastating Measles outbreaks. With vaccination rates down by 42% since the start of the pandemic and the threat of an outbreak increasing daily, there is only so much time before the situation spirals out of control.

Potential Impacts of Mass Nutritional Supplementation on Measles Dynamics: A Simulation Study.

The bidirectional interaction between undernutrition and infection can be devastating to child health. Nutritional deficiencies impair immunity and increase susceptibility to infection. Simultaneously, infections compound undernutrition by increasing metabolic demand and impairing nutrient absorption. Treatment of acute malnutrition (wasting) can reverse some of its deleterious effects and reduce susceptibility to infectious diseases. Nutrition-specific approaches may be packaged with other interventions, including immunization, to support overall child health. To understand how mass nutritional supplementation, treatment of wasting, and vaccination affect the dynamics of a vaccine-preventable infection, we developed a population-level, compartmental model of measles transmission stratified by age and nutrition status. We simulated a range of scenarios to assess the potential reductions in measles infection and mortality associated with targeted therapeutic feeding for children who are wasted and with a mass supplementation intervention. Nutrition interventions were assumed to increase engagement with the health sector, leading to increased vaccination rates. We found that the combination of wasting treatment and mass supplementation coverage followed by an increase in vaccination coverage of non-wasted children from a baseline of 75% to 85%, leads to 34% to 57% and 65% to 77% reduction in measles infection and mortality and 56% to 60% reduction in overall mortality among wasted children, compared with the wasting treatment alone. Our work highlights the synergistic benefits that may be achieved by leveraging mass nutritional supplementation as a touch point with the health system to increase rates of vaccination and improve child survival beyond what would be expected from the additive benefits of each intervention.

Assessing the Effects of Measles Virus Infections on Childhood Infectious Disease Mortality in Brazil.

Measles virus infection induces acute immunosuppression for weeks following infection, and also impairs preexisting immunological memory, resulting in "immune amnesia" that can last for years. Both mechanisms predispose the host to severe outcomes of subsequent infections. Therefore, measles dynamics could potentially affect the epidemiology of other infectious diseases. To examine this hypothesis, we analyzed the annual mortality rates of children aged 1-9 years in Brazil from 1980 to 1995. We calculated the correlation between nonmeasles infectious disease mortality rates and measles mortality rates using linear and negative-binomial models, with 3 methods to control the confounding effects of time. We also estimated the duration of measles-induced immunomodulation. The mortality rates of nonmeasles infectious diseases and measles virus infection were highly correlated. This positive correlation remained significant after removing the time trends. We found no evidence of long-term measles immunomodulation beyond 1 year. These results support that measles virus infection could increase the mortality of other infectious diseases. The short lag identified for measles effects (<1 year) implies that acute immunosuppression was potentially driving this effect in Brazil. Overall, our study indicates disproportionate contributions of measles to childhood infectious disease mortality, highlighting the importance of measles vaccination.

Differential health impact of intervention programs for time-varying disease risk: a measles vaccination modeling study

BackgroundDynamic modeling is commonly used to evaluate direct and indirect effects of interventions on infectious disease incidence. The risk of secondary outcomes (e.g., death) attributable to infection may depend on the underlying disease incidence targeted by the intervention. Consequently, the impact of interventions (e.g., the difference in vaccination and no-vaccination scenarios) on secondary outcomes may not be proportional to the reduction in disease incidence. Here, we illustrate the estimation of the impact of vaccination on measles mortality, where case fatality ratios (CFRs) are a function of dynamically changing measles incidence.MethodsWe used a previously published model of measles CFR that depends on incidence and vaccine coverage to illustrate the effects of (1) assuming higher CFR in “no-vaccination” scenarios, (2) time-varying CFRs over the past, and (3) time-varying CFRs in future projections on measles impact estimation. We used modeled CFRs in alternative scenarios to estimate measles deaths from 2000 to 2030 in 112 low- and middle-income countries using two models of measles transmission: Pennsylvania State University (PSU) and DynaMICE. We evaluated how different assumptions on future vaccine coverage, measles incidence, and CFR levels in “no-vaccination” scenarios affect the estimation of future deaths averted by measles vaccination.ResultsAcross 2000–2030, when CFRs are separately estimated for the “no-vaccination” scenario, the measles deaths averted estimated by PSU increased from 85.8% with constant CFRs to 86.8% with CFRs varying 2000–2018 and then held constant or 85.9% with CFRs varying across the entire time period and by DynaMICE changed from 92.0 to 92.4% or 91.9% in the same scenarios, respectively. By aligning both the “vaccination” and “no-vaccination” scenarios with time-variant measles CFR estimates, as opposed to assuming constant CFRs, the number of deaths averted in the vaccination scenarios was larger in historical years and lower in future years.ConclusionsTo assess the consequences of health interventions, impact estimates should consider the effect of “no-intervention” scenario assumptions on model parameters, such as measles CFR, in order to project estimated impact for alternative scenarios according to intervention strategies and investment decisions.

Innovations in vaccine delivery: increasing access, coverage, and equity and lessons learnt from measles and rubella elimination.

Disease eradication and elimination programs drive innovations based on progress toward measurable objectives, evaluations of new strategies and methods, programmatic experiences, and lessons learned from the field. Following progress toward global measles elimination, reducing measles mortality, and increasing introductions of measles and rubella vaccines to national programs, the measles and rubella immunization program has faced setbacks in recent years. Currently available vaccine delivery methods have complicated logistics and drawbacks that create barriers to vaccination; innovations for easier, more efficient, and safer vaccine delivery are needed. Progress can be accelerated by new technologies like microarray patches (MAPs) that are now widely recognized as a potential new tool for enhancing global immunizations efforts. Clinical trials of measles-rubella vaccine MAPs have begun, and several other vaccine MAPs are in the pre-clinical development pathway. MAPs could significantly contribute to Immunization Agenda 2030 priorities, including reaching zero-dose children; increasing vaccine access, demand, coverage, and equity; and achieving measles and rubella elimination. With strong partnerships between public health agencies and biotechnology companies, translational novel vaccine delivery systems can be developed to help solve public health problems and achieve global health priorities.

Measles in the European past: outbreak of severe measles in an isolated German village, 1861

We examined measles mortality in the European past in an outbreak in an isolated German village, Hagelloch, in 1861. Pfeilsticker's contemporary thesis was used to describe the measles case fatality ratio (CFR) and complications. Data on onset of prodromes and rash was used to determine index cases and secondary cases of measles within the household. The church register provided information on survival in 1862. The epidemic affected nearly all children under 14 years of age. The overall CFR was 6.4%(12/187), and 10%(7/70) for children under five years of age; 44% of children were secondary cases (82/187). Secondary cases had higher CFR than index cases (RR=3.03 (95% CI: 0.91-10.07). Boys had higher CFR than girls (RR=4.46 (1.03-19.22)). Boys infected by a girl had higher CFR than boys infected by other boys (RR=6.30 (1.18-85.64)). Children who survived measles virus infection in 1861, did not have higher mortality in the following year compared with those who had not had measles in 1861 (RR=0.24 (0.07-0.82)). Severe measles in the European past had determinants similar to those observed more recently in low-income countries. The measles case fatality was 6% in rural Germany in 1861. Mortality was highest for boys infected in the household by a girl. There was no excess mortality after the acute phase of measles infection.

Measles susceptibility in maternal-infant dyads—Bamako, Mali

Measles is endemic in Africa; measles mortality is highest among infants. Infant measles antibody titer at birth is related to maternal immune status. Older mothers are likelier to have had measles infection, which provides higher antibody titers than vaccine-induced immunity. We investigated the relationship between maternal age and measles susceptibility in mother-infant pairs in Mali through six months of infancy.We measured serum measles antibodies in 340 mother-infant pairs by plaque reduction neutralization test (PRNT) and calculated the proportion of mothers with protective titers (>120 mIU/mL) at delivery and the proportion of infants with protective titers at birth, and at three and six months of age. We explored associations between maternal age and measles antibodies in mothers and infants at the timepoints noted.Ten percent of Malian newborns were susceptible to measles; by six months nearly all were. Maternal and infant antibody titers were highly correlated. At delivery, 11% of mothers and 10% of newborns were susceptible to measles. By three and six months, infant susceptibility increased to 72% and 98%, respectively. Infants born to younger mothers were most susceptible at birth and three months. Time to susceptibility was 6.6 weeks in infants born to mothers with measles titer >120–<430 mIU/mL versus 15.4 weeks when mothers had titers ≥430 mIU/mL.Maternal and newborn seroprotective status were positively correlated. Improved strategies are needed to protect susceptible infants from measles infection and death. Increasing measles immunization coverage in vaccine eligible populations, including nonimmune reproductive-aged women and older children should be considered.

Measles Morbidity and Mortality in the Department of Child Health, Dr. Pirngadi General Hospital, Medan, in 1973-1977

One hundred seventy-six cases with measles have been hospitalized at the Department of Child Health, Dr. Pirngadi General Hospital, Medan in 1973 - 1977.&#x0D; The case fatality rate was 26.1%. The most frequent complications found were Pneumonia, Encephalitis, Diarrhea and Dehydration.&#x0D; Age specific mortality, as expected, was highest in the 0 - 1 year age group (38.6%). A high proportion of the survivors (22.2%) showed recidual signs of brain damage and blind-ness.&#x0D; This study proved that active immunization against measles in Indonesia must have priority.

Measles outbreak in the Philippines: epidemiological and clinical characteristics of hospitalized children, 2016-2019

SummaryBackgroundMeasles outbreaks increased worldwide during 2017-19. The largest outbreak in the World Health Organisation Western Pacific region occurred in the Philippines where first-dose measles-containing vaccine (MCV1) coverage had reduced to 75% in 2018. The aim of this study was to summarise paediatric measles admissions to the national infectious diseases referral hospital in Manila during 2016 to 2019.MethodsA retrospective single-centre observational study including 5,562 children aged under five years admitted with measles from January 2016 to December 2019. We summarised sociodemographic and clinical characteristics, vaccine status, reported exposures, and outcomes. Univariable and multivariable logistic regression analyses were undertaken to assess associations between different characteristics of hospitalised children and death.FindingsThe median age of children hospitalised with measles was 11 months (interquartile range: 7-28). 84·5% of cases were reported not to have received any MCV. The risk of mortality was 3·2%, with 41% of deaths occurring among children aged less than 9 months. No children died who had received two MCV. The following characteristics were significantly associated with mortality in the multivariable analysis: age group, residence outside of the national capital region, not having received any MCV, duration between onset of fever and hospital admission of 7-14 days compared with 0-3 days, not receiving vitamin A supplementation, having pneumonia, and gastroenteritis.InterpretationThe Philippines remains at risk of future measles epidemics. Routine immunization needs to be strengthened and earlier timing of MCV1 requires further evaluation to reduce measles incidence and mortality.

Analysis and Outlook for the Development of Measles Epidemic Situation during the COVID-19 Pandemic

Relevance. The success of the global community in the fight against measles through vaccination at the beginning of the twentyfirst century allowed WHO to declare the goal of eliminating this infection by 2010. However, ten years later, the problem of the growing incidence of measles has become relevant again for all countries of the world. The pandemic of the new coronavirus infection (COVID-19) has affected all spheres of human life and has exacerbated the situation in the fight against other infections, including those managed with the help of specific prophylaxis. Since the measles contagiosity index and mortality rate are significantly higher than similar characteristics of COVID-19, the risk of increasing the incidence of this infection in the coming years is difficult to overestimate.Aim of the study: to assess the epidemic situation of measles in the context of the COVID-19 pandemic, as well as the prospects for its development; to propose preventive measures.Materials and methods. The article analyzes the statistical materials available on the official websites of the WHO (WHO). https://www.who.int/data/), the CDC US (https://www. cdc.gov) and the Federal Service of Rospotrebnadzor (https://www.rospotrebnadzor.ru/) on vaccination coverage and measles incidence in 13 countries in the WHO European Region and the United States. The epidemic situation on measles, as well as the level of population coverage with vaccination against its pathogen in the Russian Federation, were assessed according to the Federal State Statistical Observation forms 2010 – 2020: Form 2 «Information on infectious and parasitic diseases» and Form 6 «Information on the populations of children and adults vaccinated against infectious diseases».Results. It has been established that the increase in the measles incidence occurred in 2017–2019 worldwide, including European countries with a population coverage of two vaccine doses at the 97% level between 2010 and 2019. The prevalence of measles cases in children under the age of 10 is shown, as well as the wide range (from 56.9% to 10.9%) in the proportion of vaccinated persons among them. The results obtained indicate the existence of problems in the organization of modern vaccine prevention. The introduction of widespread restrictive and quarantine measures against the COVID-19 pandemic, on the one hand, has reduced the incidence of measles and, on the other hand, has exacerbated the difficulties in implementing measles prevention. Thus, the results indicate a possible increase in measles incidence in the population after the end of the COVID-19 pandemic.Conclusion. It is necessary to immediately develop an action plan to catch up on the coverage and increase the rate of routine vaccination, to improve the statistical record of persons subject to the introduction of the vaccine and vaccinated, as well as to overcome anti-vaccination attitude among the population.

Epidemiology of Measles in Bale Zone, Southeast Ethiopia: Analysis of Surveillance Data from 2013 to 2019.

BackgroundMeasles remains a cause of vaccine-preventable death in children worldwide. Reported cases in Ethiopiarepresent only a small proportion of expected cases, due to weak measles-based surveillance implementation. In this study, we aimed to analyze 7 years’ measles-surveillance data from Bale zone, in order to indicate measles epidemiology and surveillance-related gaps.MethodsThis cross-sectional study was conducted from May to June 2019. The study population was all measles cases reported to the Bale Zone Health Office from 2013 to 2019. Data were abstracted from 7 years’ measles line lists and case-based reports using a data-abstraction check-list. Data were analyzed using Microsoft Excel and Pivot software, and were presented in tables and graphs.ResultsOverall, 4,241 measles cases were reported from 2013 to 2019. Mean age was 7.15 years, and 50.6% were male. The most affected age-group was children <4 years of age. Analysis indicated that the case-fatality rate was 3.07/1,000 population. Of the total cases reported, 248 (5.8%) were IgM-confirmed. The highest prevalence of 141/100,000 population was reported in 2019. Unvaccinated cases and those with unknown vaccination status numbered 890 (21%) and 731 (17.2%), respectively. The highest number of cases was reported from Ginir and Gololcha districts. Cases increased in autumn each year and peaked in May.ConclusionMeasles is a major cause of morbidity and mortality in Bale, due to poor immunization coverage. Its case fatality is also high, excluding community deaths. Of all the districts included, Ginir reported the highest number of cases. Improving vaccination coverage, early preparedness for the annual epidemic cycle, and strengthening case-based surveillance are important interventions to reduce measles morbidity and mortality.

Febrile Seizures and Measles-Containing Vaccines in China: A Self-Controlled Case Series Study.

Little is known about the risk of febrile seizures (FS) after vaccination with measles-containing vaccines (MCVs) in middle- and low-income countries. This self-controlled case series study aimed to evaluate the risk of FSs in Chinese children using data from the Ningbo Regional Health Information Platform. The observation period was 0–12 and 13–24 months of age for the MR and MMR vaccines, respectively. The relative incidences (RIs) within 0–6 days, 7–13 days, 14–27 days, and 28–42 days after vaccination with MCVs were estimated. The remaining observation period was the control period. The RIs within 0–6 days, 7–13 days, 14–27 days, and 28–42 days after MR vaccination were 1.11 [95% confidence interval (CI) 0.33 to 3.70], 0.80 (95% CI 0.23 to 2.86), 1.67 (95% CI 0.81 to 3.42), and 1.02 (95% CI 0.49 to 2.14), respectively. The corresponding RIs after MMR vaccination were 0.99 (95% CI 0.56 to 1.75), 1.17 (95% CI 0.68 to 2.01), 0.87 (95% CI 0.54 to 1.39), and 0.85 (95% CI 0.54 to 1.34), respectively. This study suggests that China’s vaccination schedule for MCVs, as suggested by the World Health Organization (WHO) for countries with a high risk of measles mortality and ongoing transmission, does not increase the risk of FSs.

Incorporating equity in infectious disease modeling: Case study of a distributional impact framework for measles transmission

IntroductionDeterministic compartmental models of infectious diseases like measles typically reflect biological heterogeneities in the risk of infection and severity to characterize transmission dynamics. Given the known association of socioeconomic status and increased vulnerability to infection and mortality, it is also critical that such models further incorporate social heterogeneities. MethodsHere, we aimed to explore the influence of integrating income-associated differences in parameters of traditional dynamic transmission models. We developed a measles SIR model, in which the Susceptible, Infected and Recovered classes were stratified by income quintile, with income-specific transmission rates, disease-induced mortality rates, and vaccination coverage levels. We further provided a stylized illustration with secondary data from Ethiopia, where we examined various scenarios demonstrating differences in transmission patterns by income and in distributional vaccination coverage, and quantified impacts on disparities in measles mortality. ResultsThe income-stratified SIR model exhibited similar dynamics to that of the traditional SIR model, with amplified outbreak peaks and measles mortality among the poorest income group. All vaccination coverage strategies were found to substantially curb the overall number of measles deaths, yet most considerably for the poorest, with select strategies yielding clear reductions in measles mortality disparities. DiscussionThe incorporation of income-specific differences can reveal distinct outbreak patterns across income groups and important differences in the subsequent effects of preventative interventions like vaccination. Our case study highlights the need to extend traditional modeling frameworks (e.g. SIR models) to be stratified by socioeconomic factors like income and to consider ensuing income-associated differences in disease-related morbidity and mortality. In so doing, we build on existing tools and characterize ongoing challenges in achieving health equity.