Measles Control Research Articles

Estimating the optimal age for infant measles vaccination.

The persistence of measles in many countries demonstrates large immunity gaps, resulting from incomplete or ineffective immunization with measles-containing vaccines (MCVs). MCV impact is determined, in part, by vaccination age. Infants who receive dose 1 (MCV1) at older ages have a reduced risk of vaccine failure, but also an increased risk of contracting infection before vaccination. Here, we designed a new method-based on a mathematical transmission model incorporating realistic vaccination delays and age variations in MCV1 effectiveness-to capture the MCV1 age risk trade-off and estimate the optimal age for recommending MCV1. We applied this method to a range of synthetic populations representing lower- and higher-income populations. We predict a large heterogeneity in the optimal MCV1 ages (range: 6-20 months), contrasting the homogeneity of observed recommendations worldwide. Furthermore, we show that the optimal age depends on the local epidemiology of measles, with a lower optimal age predicted in populations having lower vaccination coverage or suffering higher transmission. Overall, our results suggest the scope for public health authorities to tailor the recommended schedule for better measles control.

The Health and Economic Benefits of United States Investments in Measles and Rubella Control and Elimination

Background: Prior to measles vaccine introduction in 1963, measles virus caused hundreds of thousands of annual reported cases, which led to substantial US morbidity, mortality, and costs. Similarly, congenital rubella syndrome (CRS) led to highly visible and tragic lifelong disability for thousands of Americans, before rubella vaccine introduction in 1969. The US certified national virus transmission elimination of indigenous measles in 2000 and rubella in 2004. Methods: Applying an existing integrated transmission and economic model, this analysis characterizes the net benefits of US investments in measles (1963–2030) and rubella (1969–2030) immunization assuming continued high routine immunization coverage. Due to importation risks, the US maintains two doses of both vaccines in its routine immunization schedule. Results: This analysis estimates total US costs of 8.1 billion (economics reported in 2023 US dollars) for measles immunization for 1963–2023 and 14.1 billion for rubella immunization for 1969–2023. The analysis estimates an additional approximately 1.2 billion for measles immunization and 1.5 billion for rubella immunization expected for 2024–2030. Historical and future US investments prevented an estimated approximately 237 million measles infections, 228,000 measles deaths, 193 million rubella infections, and 166,000 CRS cases. These investments imply net benefits (from avoided treatment costs minus immunization costs) of approximately 310 billion for measles and 430 billion for rubella and CRS, even without incorporating avoided productivity losses and intangible costs. Conclusions: US investments in measles and rubella immunization continue to provide enormous savings of human and financial costs and to prevent substantial mortality and morbidity.

Long-term waning of vaccine-induced immunity to measles in England: a mathematical modelling study

Among people infected with measles in England between 2010 and 2019, the proportion of cases who had previously received two doses of vaccine has increased, especially among young adults. Possible explanations include rare infections in vaccinated individuals who did not gain immunity upon vaccination, made more common because fewer individuals in the population were born in the endemic era, before vaccination was introduced, and exposed as part of endemic transmission, or the waning of vaccine-induced immunity, which would present new challenges for measles control in near-elimination settings. We aimed to evaluate whether measles dynamics observed in England between 2010 and 2019 were in line with a waning of vaccine-induced immunity. We used a compartmental mathematical model stratified by age group, region, and vaccine status, fitted to individual-level case data reported in England from 2010 to 2019 and collected by the UK Health Security Agency. The deterministic model was fitted using Monte Carlo Markov Chains under three scenarios: without the waning of vaccine-induced immunity, with waning depending on time since vaccination, and with waning depending on time since vaccination, starting in 2000. We generated stochastic simulations from the fitted parameter sets to evaluate which scenarios could replicate the transmission dynamics observed in vaccinated cases in England. The scenario without waning overestimated the number of one-dose recipients among measles cases, and underestimated the number of two-dose recipients among cases older than 15 years (median 75 cases [95% simulation interval (SI) 44-124] in simulations without waning, 196 [95% SI 122-315] in simulations when waning was included, 188 [95% SI 118-301] in simulations when waning started in 2000, and 202 observed cases). The number of onward transmissions from vaccinated cases was 83% (95% credible interval 72-91%) of the number of transmissions from unvaccinated cases. The estimated waning rate was slow (0·039% per year of age; 95% credible interval 0·034-0·044% per year in the best-fitting scenario with waning starting in 2000), but sufficient to increase measles burden. Measles case dynamics in England are consistent with scenarios assuming the waning of vaccine-induced immunity. Since measles is highly infectious, slow waning leads to a heightened burden in outbreaks, increasing the number of measles cases in people who are both vaccinated and unvaccinated. Our findings show that although the vaccine remains highly protective against measles infections for decades and most transmission is connected to people who are unvaccinated, breakthrough infections are increasingly frequent for individuals aged 15 years and older who have been vaccinated twice. National Institute for Health and Care Research and Wellcome Trust.

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

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

Modelling the Impact of Vaccination on the Control of Measles in Nepal

Measles is a highly contagious disease in human caused by virus. Despite the accessibility of successful vaccines, measles outbreaks still occur, presumably because of the lack of compliance with vaccination. We developed a mathematical model to evaluate the effects of vaccines in different age structures particularly focusing on two groups, to control and eradicate the disease, that may help the planner. Using our model, we formulate the basic reproduction number R 0 that determines, whether the disease persists or dies out. In addition, we carry out sensitivity analysis to identify important parameters that can play a significant role in the control and prevention of measles in different groups of individuals. Furthermore, we investigate the behavior of the disease and effect of vaccination on disease dynamics over a long period.

A mathematical analysis of the impact of maternally derived immunity and double-dose vaccination on the spread and control of measles

Abstract Measles is a highly communicable viral infection that mostly affects children aged 5 years and below. Maternal antibodies in neonates help protect them from infectious diseases, including measles. However, maternal antibodies disappear a few months after birth, necessitating vaccination against measles. A mathematical model of measles, incorporating maternal antibodies and a double-dose vaccination, was proposed. Whenever ℛ 0 < 1 {{\mathcal{ {\mathcal R} }}}_{0}\lt 1 , the model is shown to be locally asymptotically stable. This means that the measles disease can be eliminated under such conditions in a finite time. It was established that ℛ 0 {{\mathcal{ {\mathcal R} }}}_{0} is highly sensitive to β \beta (the transmission rate). A numerical simulation of the model using the Runge-Kutta fourth-order scheme was carried out, showing that varying the parameters to reduce ℛ 0 {{\mathcal{ {\mathcal R} }}}_{0} will help control the measles disease and ultimately lead to eradication. The measles-mumps-rubella (MMR) vaccine dosage should be adjusted for babies from recovered mothers, as maternal antibodies are usually high in such babies and can interfere with the effectiveness of the MMR vaccine.

The Incidence of Measles Infection in Southern Vietnam during COVID-19 Pandemic

The paper presents data on measles cases identified in 18 provinces of South Vietnam (SV) in 2020, during the active phase of the pandemic of the new coronavirus SARS-CoV2. The measles virus actively circulated in SV in the first months of 2020: the average measles incidence rate was 1.27 per 100,000 population. Children under 5 years of age dominated in the age structure (71%). The vast majority of cases are people who have not been vaccinated against measles, as well as people who do not have information about vaccinations; in total, their share was 97.4%, but there were vaccinated and revaccinated individuals among the sick. Significantly more often, IgM-measles antibodies were recorded in samples obtained from the city of Can Tho, (n=57) where the infectious diseases hospital is located, receiving patients from neighboring regions of the SV. The largest number of measles cases were also recorded in the provinces of Dong Thap (n=57), Hao Glang (n=62) and Ho Chi Minh City (n=15). That is, residents of large cities, industrial and the medical centers were primarily involved in the measles epidemic process. A sharp decrease in the incidence of measles has been shown since April 2020, when measures to limit the spread of COVID-19 were introduced in SV. It should be noted that violations of vaccination associated with the COVID-19 pandemic, after the lifting of sanitary and epidemiological restrictions, may lead to increased morbidity and the development of measles outbreaks in Vietnam and other countries involved in the pandemic. Therefore, preventing future outbreaks will require strengthening measles surveillance and control measures to achieve its elimination.

Estimation of the relationship between meteorological factors and measles using spatiotemporal Bayesian model in Shandong Province, China

BackgroundMeasles-containing vaccine (MCV) has been effective in controlling the spread of measles. Some countries have declared measles elimination. But recently years, the number of cases worldwide has increased, posing a challenge to the global goal of measles eradication. This study estimated the relationship between meteorological factors and measles using spatiotemporal Bayesian model, aiming to provide scientific evidence for public health policy to eliminate measles.MethodsDescriptive statistical analysis was performed on monthly data of measles and meteorological variables in 136 counties of Shandong Province from 2009 to 2017. Spatiotemporal Bayesian model was used to estimate the effects of meteorological factors on measles, and to evaluate measles risk areas at county level. Case population was divided into multiple subgroups according to gender, age and occupation. The effects of meteorological factors on measles in subgroups were compared.ResultsSpecific meteorological conditions increased the risk of measles, including lower relative humidity, temperature, and atmospheric pressure; higher wind velocity, sunshine duration, and diurnal temperature variation. Taking lowest value (Q1) as reference, RR (95%CI) for higher temperatures (Q2–Q4) were 0.79 (0.69–0.91), 0.54 (0.44–0.65), and 0.48 (0.38–0.61), respectively; RR (95%CI) for higher relative humidity (Q2–Q4) were 0.76 (0.66–0.88), 0.56 (0.47–0.67), and 0.49 (0.38–0.63), respectively; RR (95%CI) for higher wind velocity (Q2–Q4) were 1.43 (1.25–1.64), 1.85 (1.57–2.18), 2.00 (1.59–2.52), respectively. 22 medium-to-high risk counties were identified, mainly in northwestern, southwestern and central Shandong Province. The trend was basically same in the effects of meteorological factors on measles in subgroups, but the magnitude of the effects was different.ConclusionsMeteorological factors have an important impact on measles. It is crucial to integrate these factors into public health policies for measles prevention and control in China.

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

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

Resurgence of measles infection among children: findings from a surveillance-based population study

Background There has been a resurgence of measles infection in countries with high vaccination rates, including Malaysia. Understanding the geographical variation in measles resurgence and associated factors is important for measles prevention and control programs, especially where local information is scarce.
 Objective To determine the incidence of laboratory-confirmed measles infection and associated factors in the state of Melaka, in the southern region of Malaysia.
 Methods We obtained measles surveillance data for 4 years (January 2015 to December 2018) from the e-Measles national database. A comparative cross-sectional study was carried out on these data involving children who had been selected through convenience sampling.
 Results A total of 130 laboratory-confirmed measles cases and 213 non-measles cases were included in the study. Among the laboratory-confirmed cases, 56 (43.1%) had not been vaccinated against measles virus. Thirty-eight cases (51.4%) had received at least one dose of measles vaccine, while 36 cases (48.6%) had completed two doses of measles vaccination. There was a higher risk of contracting laboratory-confirmed measles among unvaccinated children (OR 19.39, 95%CI 8.82 to 42.6, P<0.001) and children aged 8–18 years (OR 0.40, 95% CI 0.21 to 0.76, P=0.005)
 Conclusion Unvaccinated children and children aged 8–18 years have a higher risk of contracting laboratory-confirmed measles. The policy on routine immunization should be strengthened, the vaccine should be accessible to all children, and all children and adolescents should be given booster vaccinations.

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.

Measles Serostatus in Mothers and Their Newborns in Antioquia, Colombia: Implications for Measles Elimination.

To describe the serostatus of measles IgG antibodies in pregnant women and newborns, placental transfer, and factors that determine being below the threshold of 150 mIU/mL, a cross-sectional study was conducted. Blood samples of 790 pregnant women at the time of delivery and 734 umbilical cord samples were analyzed from eight hospitals in the Aburrá Valley of Antioquia, Colombia. Measles IgG antibody measurement was performed with ELISA. The proportion of individuals with antibodies < 150 mIU/mL was 13.9% (95% CI: 12.2-15.8) in pregnant women and 11.1% (95% CI: 9.2-13.4) in newborns. The geometric mean of the antibody level of the pregnant women was 552 mIU/mL (95% CI: 504-605) and in the umbilical cord 662 mIU/mL (95% CI: 604-727). A positive correlation between pregnant woman and umbilical cord antibodies was found. The median ratio of measles IgG antibodies in umbilical cord/pregnant woman was 1.22 for all participants. A seroprevalence below the threshold of 150 mIU/mL was found in newborns whose mothers were born between 1983 and 1994, compared with those born before that period, when exposure to the wildtype virus was common (adjusted prevalence ratio: 3.6, 95% CI: 1.3-9.6). These findings suggest that there are gaps in measles immunity among women of childbearing age, before pregnancy. To close this immune gap and support efforts to maintain measles control, serological screening for measles antibodies should be routinely included in reproductive health and antenatal care programs to identify women without immunity who should be vaccinated before pregnancy or after delivery.

Progress Toward Measles and Rubella Elimination — India, 2005–2021

In 2019, India, along with other countries in the World Health Organization (WHO) South-East Asia Region,* adopted the goal of measles and rubella elimination by 2023,† a revision of the previous goal of measles elimination and control of rubella and congenital rubella syndrome (CRS) by 2020§ (1-3). During 2017-2021, India adopted a national strategic plan for measles and rubella elimination (4), introduced rubella-containing vaccine (RCV) into the routine immunization program, launched a nationwide measles-rubella supplementary immunization activity (SIA) catch-up campaign, transitioned from outbreak-based surveillance to case-based acute fever and rash surveillance, and more than doubled the number of laboratories in the measles-rubella network, from 13 to 27. Strategies included 1) achieving and maintaining high population immunity with at least 95% vaccination coverage by providing 2 doses of measles- and rubella-containing vaccines; 2) ensuring a sensitive and timely case-based measles, rubella and CRS surveillance system; 3) maintaining an accredited measles and rubella laboratory network; 4) ensuring adequate outbreak preparedness and rapid response to measles and rubella outbreaks; and 5) strengthening support and linkages to achieve these strategies, including planning and progress monitoring, advocacy, social mobilization and communication, identification and utilization of synergistic linkages of integrated program efforts, research, and development. This report describes India's progress toward the elimination of measles and rubella during 2005-2021, with a focus on the years 2017-2021.¶ During 2005-2021, coverage with the first dose of a measles-containing vaccine (MCV) administered through routine immunization increased 31%, from 68% to 89%. During 2011-2021, coverage with a second MCV dose (MCV2) increased by 204%, from 27% to 82%. During 2017-2021, coverage with a first dose of RCV (RCV1) increased almost 14-fold, from 6% to 89%. More than 324 million children received a measles- and rubella-containing vaccine (MRCV) during measles-rubella SIAs completed in 34 (94%) of 36 states and union territories (states) during 2017-2019. During 2017-2021, annual measles incidence decreased 62%, from 10.4 to 4.0 cases per 1 million population, and rubella incidence decreased 48%, from 2.3 to 1.2 cases per 1 million population. India has made substantial progress toward measles and rubella elimination; however, urgent and intensified efforts are required to achieve measles and rubella elimination by 2023.

The impact of supplementary immunization activities on measles transmission dynamics and implications for measles elimination goals: A mathematical modelling study

BackgroundMeasles has re-emerged globally due to the accumulation of susceptible individuals and immunity gap, which causes challenges in eliminating measles. Routine vaccination and supplementary immunization activities (SIAs) have greatly improved measles control, but the impact of SIAs on the measles transmission dynamics remains unclear as the vaccine-induced immunity wanes. MethodsWe developed a comprehensive measles transmission dynamics model by taking into account population demographics, age-specific contact patterns, seasonality, routine vaccination, SIAs, and the waning vaccine-induced immunity. The model was calibrated by the monthly age-specific cases data from 2005 to 2018 in Jiangsu Province, China, and validated by the dynamic sero-prevalence data. We aimed to investigate the short-term and long-term impact of three-time SIAs during 2009–2012 (9.68 million and 4.25 million children aged 8 months-14 years in March 2009 and September 2010, respectively, and 140,000 children aged 8 months-6 years in March 2012) on the measles disease burden and explored whether additional SIAs could accelerate the measles elimination. ResultsWe estimated that the cumulative numbers of measles cases from March 2009 to December 2012 (in the short run) and to December 2018 (in the long run) after three-time SIAs (base case) were 6,699 (95% confidence interval [CI]: 2,928–10,469), and 22,411 (15,146–29,675), which averted 45.0% (42.9%-47.0%) and 34.3% (30.7%-37.9%) of 12,226 (4,916–19,537) and 34,274 (21,350–47,199) cases without SIAs, respectively. The fraction of susceptibles for children aged 8–23 months and 2–14 years decreased from 8.3% and 10.8% in March 2009 to 5.8% and 5.8% in April 2012, respectively. However, the fraction of susceptibles aged 15–49 years and above 50 years increased gradually to about 15% in 2018 irrespective of SIAs due to the waning immunity. The measles elimination goal would be reached in 2028, and administrating additional one-off SIAs in September 2022 to children aged 8–23 months, or young adolescents aged 15–19 years could accelerate the elimination one year earlier. ConclusionsSIAs have greatly reduced the measles incidence and the fraction of susceptibles, but the benefit may wane over time. Under the current interventions, Jiangsu province would reach the measles elimination goal in 2028. Additional SIAs may accelerate the measles elimination one year earlier.

Measles: Global Indicators and Progress on the road for Achieving and Sustaining Virus Eradication: A Review

Measles morbillivirus is regarded as one of the most influential contagious virus in the timeline of human history. Before the classification of this virus and formulation of early vaccines in the starting 1960s, it was responsible for killing 0.1 – 10 % of every birth cohort. While live-attenuated samples of measles morbillivirus have considerably mitigated fatality rate around 99% in developed states, - 1 million fatalities are nevertheless occurring on yearly basis in the developing states, and multiple queries are awaiting response regarding immune-pathogenesis of measles, the vaccines and correlates of immunity itself. This study analyzes the considerable influence of vaccination uptake brought upon the reduction of measles disease burden all over the world, the foundation of effective vaccines along with their effectiveness and safety profiles, worldwide scenario of vaccination, the economic potential of investment in effective vaccines, the multiple impediments observed in control of measles in modern years, along with the major issues that have to be tackled for achieving a planet free from measles.

Health effects of utilising hospital contacts to provide measles vaccination to children 9\u201359\u2009months\u2014a randomised controlled trial in Guinea-Bissau

BackgroundMeasles vaccination coverage in Guinea-Bissau is low; fewer than 80% of children are currently measles vaccinated before 12 months of age. The low coverage hampers control of measles. Furthermore, accumulating evidence indicates that measles vaccine has beneficial non-specific effects, strengthening the resistance towards other infections. Thus, even if children are not exposed to measles virus, measles-unvaccinated children may be worse off. To increase vaccination coverage, WHO recommends that contacts with the health system for mild illness are utilised to vaccinate. Currently, in Guinea-Bissau, curative health system contacts are not utilised.MethodsBandim Health Project registers out-patient consultations and admissions at the paediatric ward of the National Hospital in Guinea-Bissau. Measles-unvaccinated children aged 9–59 months consulting for milder illness or being discharged from the paediatric ward will be invited to participate in a randomised trial. Among 5400 children, randomised 1:1 to receive standard measles vaccine or a saline placebo, we will test the hypothesis that providing a measles vaccine at discharge lowers the risk of admission/mortality (composite outcome) during the subsequent 6 months by 25%. All enrolled children are followed through the Bandim Health Project registration system and through telephone follow-up. The first 1000 enrolled children are furthermore followed through interviews on days 2, 4, 7 and 14 after enrolment.DiscussionUtilising missed vaccination opportunities can increase vaccination coverage and may improve child health. However, without further evidence for the safety and potential benefits of measles vaccination, these curative contacts are unlikely to be used for vaccination in Guinea-Bissau.Trial registrationwww.ClinicalTrials.gov NCT04220671. Registered on 5 January 2020.

Modeling transmission dynamics of measles in Nepal and its control with monitored vaccination program.

Measles is one of the highly contagious human viral diseases. Despite the availability of vaccines, measles outbreak frequently occurs in many places, including Nepal, partly due to the lack of compliance with vaccination. In this study, we develop a novel transmission dynamics model to evaluate the effects of monitored vaccination programs to control and eliminate measles. We use our model, parameterized with the data from the measles outbreak in Nepal, to calculate the vaccinated reproduction number, $ R_v $, of measles in Nepal. We perform model analyses to establish the global asymptotic stability of the disease-free equilibrium point for $ R_v < 1 $ and the uniform persistence of the disease for $ R_v > 1 $. Moreover, we perform model simulations to identify monitored vaccination strategies for the successful control of measles in Nepal. Our model predicts that the monitored vaccination programs can help control the potential resurgence of the disease.

Mitigating the Spread of Measles under Constrained Health Care Resources in Tanzania using Social Contact Network Models

Tanzania revaccinates individuals during measles outbreaks, despite having scant healthcare resources. We construct epidemiological models of measles spread by employing a hybrid of existing social contact networks models to develop SEIR simulation model. Using demographic and measles surveillance data from three rural villages in Tanzania, we simulate the spread of measles and examine which vaccination strategies can effectively control outbreaks. Results strongly indicate the spread of measles largely depends on contact rates among infected individuals within a population. Findings indicate a need for targeted vaccination for children of 6 months to 15 years of age, but equally for unvaccinated older age groups who were born before 1957 or missed the second dose. This work contributes theoretically and methodologically to existing applications of social contact network models for airborne infectious diseases in areas with health system constraints. It sets out implications for the design of effective vaccination programs for control of measles in Tanzania and in other developing countries.&#x0D; Keywords: Vaccination strategies, Control strategies, Social contact network models, Airborne infectious diseases, Measles.

Maintenance of Measles Elimination Status in the United States for 20 Years Despite Increasing Challenges.

Measles elimination (interruption of endemic measles virus transmission) in the United States was declared in 2000; however, the number of cases and outbreaks have increased in recent years. We characterized the epidemiology of measles outbreaks and measles transmission patterns after elimination to identify potential gaps in the US measles control program. We analyzed national measles notification data from 1 January 2001 to 31 December 2019. We defined measles infection clusters as single cases (isolated cases not linked to additional cases), 2-case clusters, or outbreaks with ≥3 linked cases. We calculated the effective reproduction number (R) to assess changes in transmissibility and reviewed molecular epidemiology data. During 2001-2019, a total of 3873 measles cases, including 747 international importations, were reported in the United States; 29% of importations were associated with outbreaks. Among 871 clusters, 69% were single cases and 72% had no spread. Larger and longer clusters were reported since 2013, including 7 outbreaks with >50 cases lasting >2 months, 5 of which occurred in known underimmunized, close-knit communities. No measles lineage circulated in a single transmission chain for >12 months. Higher estimates of R were noted in recent years, although R remained below the epidemic threshold of 1. Current epidemiology continues to support the interruption of endemic measles virus transmission in the United States. However, larger and longer outbreaks in recent postelimination years and emerging trends of increased transmission in underimmunized communities emphasize the need for targeted approaches to close existing immunity gaps and maintain measles elimination.

How Australia's measles control activities have catalyzed rubella elimination

BackgroundBy 2017, rubella had been officially eliminated in Australia. This success was attributed to Australia's longstanding national immunization programme and two enhanced measles immunization activities using measles, mumps, and rubella (MMR) vaccines — the Measles Control Campaign (MCC) and the Young Adult MMR Campaign (YAC). Our study describes the impact of these activities on rubella incidence, and its elimination in Australia. MethodsAggregate national serological survey data were assigned to birth cohorts, and mean, median, and age-group estimates calculated and analyzed against MMR immunization coverage estimates (1998–2018) and rubella notifications (1993–2018). Three-year cumulative incidences were calculated by birth cohort. ResultsThe serological surveys revealed high and stable levels of rubella immunity among females, but estimates for three male cohorts were lower. Since 2007, MMR immunization coverage among children aged 24–27 months has remained above 90% for both doses. The 3-year cumulative incidence of rubella declined across all birth cohorts following the MCC and the YAC. DiscussionUsing MMR vaccines to address measles immunity gaps had the additional benefit of controlling rubella in Australia. Both the MCC and YAC shifted rubella epidemiology, accelerating the interruption of endemic transmission. Countries should consider combined measles and rubella vaccines for all catch-up activities.