Measles Elimination Status Research Articles

Epidemiological characteristics of the 2019 Measles outbreak in central Tunisia

Abstract Background Measles is still an important public health problem worldwide causing significant morbidity and mortality. Measles represents a vaccine-preventable disease. In Tunisia, vaccination against measles was launched in 1983. In spite of the progress made towards measles elimination, Tunisia experienced an outbreak in 2019. We aimed to describe the measles outbreak in the central region of Tunisia in 2019. Methods We carried out a descriptive study using surveillance data from January to December 2019 in four governorates in Tunisia (Monastir, Mahdia, Kairouan, and Kasserine). All suspected measles cases and declared to regional directorate of primary health care were included. A suspected measles case was defined as any person with fever and generalized maculo-papular rash plus one of the following symptoms: cough or coryza or conjunctivitis. A laboratory confirmed measles case is a suspected case of measles that has been confirmed positive by testing (IgM+). Results A total of 2,688 suspected cases were recorded, of which 369 cases were (14.7%) were confirmed measles through serological testing. The sex ratio was 1.06 for suspected cases and 1.12 for measles cases. Infants under one year old accounted 42.2% of suspected cases. The majority of suspected cases (67.3%) were not vaccinated. Among confirmed measles cases, positivity rates were 81.8% for unvaccinated, 70.0% for those with one dose and 27.2% for those with two doses. The hospitalization rate was 61.5 %; highest rates were observed in infants under one year of age (65.7%) and in the age group over 38 years (69.0%). In total, 27 deaths were reported. The highest lethality rate was observed in the age group under 12 months (2%). Conclusions The 2019 measles outbreak in Tunisia highlighted that this disease remains a serious viral infection. Unvaccinated populations could be a potential source for new outbreaks, imposing substantial public health burdens. Key messages • The country needs to establish a national review committee to monitor measles elimination status. • To address future challenges, immunity gaps in the population should be closed.

Epidemiologic Analysis of a Postelimination Measles Outbreak in Central Ohio, 2022-2023

Postelimination outbreaks threaten nearly a quarter century of measles elimination in the US. Understanding these dynamics is essential for maintaining the nation's measles elimination status. To examine the demographic characteristics and transmission dynamics of the 2022 to 2023 central Ohio measles outbreak. This cross-sectional study used electronic medical records and publicly available measles reports within an extensive central Ohio primary care network involving inpatient and outpatient settings. Participants included 90 children in Ohio with confirmed measles cases in 2022. The exposure of interest was confirmed measles cases in Ohio in 2022. This included 5 internationally imported cases and 85 locally acquired cases. The primary outcome involved documenting and analyzing confirmed measles cases in Ohio in 2022, focusing on demographic characteristics, immunization status, and transmission links in outbreak-related cases. This study analyzed 90 measles cases (47 [52.2%] male participants) in Ohio during 2022. Most participants self-identified as African or American Black (72 [80.0%]), with additional race categories including Asian, Hispanic, multirace (6 [6.7%]), White, and unknown (6 [6.7%]). Most participants were of Somali descent (64 [71.1%]), with additional ethnicity categories including American (16 [17.8%]), Guatemalan, Nepali, and unknown (6 [6.7%]). Participants were predominantly younger than 6 years (86 [95.5%]), unimmunized (89 [98.9%]), and resided in Franklin County, Ohio (83 [92.2%]). Prior to November 20, 2022, all cases occurred among unimmunized children of Somali descent in the Columbus area. Nosocomial superspreading events expanded the outbreak beyond the initially affected community. This cross-sectional study of measles cases in Ohio during 2022 found that the outbreak primarily affected unimmunized children of Somali descent, highlighting the necessity for culturally tailored public health strategies to maintain measles elimination in the US. These findings underscore the importance of implementing targeted interventions and enhancing community engagement to increase vaccination rates.

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.

Challenges for Sustaining Measles Elimination: Post-Verification Large-Scale Import-Related Measles Outbreaks in Mongolia and Cambodia, Resulting in the Loss of Measles Elimination Status.

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.

Measles - United States, January 1, 2020-March 28, 2024.

Measles is a highly infectious febrile rash illness and was declared eliminated in the United States in 2000. However, measles importations continue to occur, and U.S. measles elimination status was threatened in 2019 as the result of two prolonged outbreaks among undervaccinated communities in New York and New York City. To assess U.S. measles elimination status after the 2019 outbreaks and to provide context to understand more recent increases in measles cases, CDC analyzed epidemiologic and laboratory surveillance data and the performance of the U.S. measles surveillance system after these outbreaks. During January 1, 2020-March 28, 2024, CDC was notified of 338 confirmed measles cases; 97 (29%) of these cases occurred during the first quarter of 2024, representing a more than seventeenfold increase over the mean number of cases reported during the first quarter of 2020-2023. Among the 338 reported cases, the median patient age was 3 years (range=0-64 years); 309 (91%) patients were unvaccinated or had unknown vaccination status, and 336 case investigations included information on ≥80% of critical surveillance indicators. During 2020-2023, the longest transmission chain lasted 63 days. As of the end of 2023, because of the absence of sustained measles virus transmission for 12 consecutive months in the presence of a well-performing surveillance system, U.S. measles elimination status was maintained. Risk for widespread U.S. measles transmission remains low because of high population immunity. However, because of the increase in cases during the first quarter of 2024, additional activities are needed to increase U.S. routine measles, mumps, and rubella vaccination coverage, especially among close-knit and undervaccinated communities. These activities include encouraging vaccination before international travel and rapidly investigating suspected measles cases.

Guarding the gatekeepers: a comprehensive approach to control nosocomial measles.

Despite substantial vaccination progress, persistent measles outbreaks challenge global elimination efforts, particularly within healthcare settings. In this paper, we critically review the factors contributing to measles outbreak and effective control measures for nosocomial transmission of measles. We systematically searched electronic databases for articles up to 17th May, 2023. This was performed by two independent reviewers, with any disagreements resolved by a third reviewer. We also searched governmental and international health agencies for relevant studies. Forty relevant articles were systematically reviewed, revealing key factors fuelling measles outbreak in healthcare settings, including high transmissibility capability; high intensity exposure; delayed care; failure to use protective equipment and implement control measures; vaccine failure; unclear immunisation history and lack of registries; and lacking recommendation on healthcare workers' (HCWs) measles vaccination. To combat these challenges, successful control strategies were identified which include early notification of outbreak and contact tracing; triaging all cases and setting up dedicated isolation unit; strengthening protective equipment use and physical measures; improving case detection; determining immunity status of HCWs; establishing policy for measles vaccination for HCWs; management of exposed personnel; and developing a pre-incident response plan. A coordinated and comprehensive approach is essential to promptly identify and manage measles cases within healthcare settings, necessitating multifactorial strategies tailored to individual settings. These findings provide a valuable foundation for refining strategies to achieve and maintain measles elimination status in healthcare environments.

Comparison of measles IgG enzyme immunoassays (EIA) versus plaque reduction neutralization test (PRNT) for measuring measles serostatus: a systematic review of head-to-head analyses of measles IgG EIA and PRNT

BackgroundAs countries move towards or achieve measles elimination status, serosurveillance is an important public health tool. However, a major challenge of serosurveillance is finding a feasible, accurate, cost-effective, and high throughput assay to measure measles antibody concentrations and estimate susceptibility in a population. We conducted a systematic review to assess, characterize, and – to the extent possible – quantify the performance of measles IgG enzyme-linked assays (EIAs) compared to the gold standard, plaque reduction neutralization tests (PRNT).MethodsWe followed the PRISMA statement for a systematic literature search and methods for conducting and reporting systematic reviews and meta-analyses recommended by the Cochrane Screening and Diagnostic Tests Methods Group. We identified studies through PubMed and Embase electronic databases and included serologic studies detecting measles virus IgG antibodies among participants of any age from the same source population that reported an index (any EIA or multiple bead-based assays, MBA) and reference test (PRNT) using sera, whole blood, or plasma. Measures of diagnostic accuracy with 95% confidence intervals (CI) were abstracted for each study result, where reported.ResultsWe identified 550 unique publications and identified 36 eligible studies for analysis. We classified studies as high, medium, or low quality; results from high quality studies are reported. Because most high quality studies used the Siemens Enzygnost EIA kit, we generate individual and pooled diagnostic accuracy estimates for this assay separately. Median sensitivity of the Enzygnost EIA was 92.1% [IQR = 82.3, 95.7]; median specificity was 96.9 [93.0, 100.0]. Pooled sensitivity and specificity from studies using the Enzygnost kit were 91.6 (95%CI: 80.7,96.6) and 96.0 (95%CI: 90.9,98.3), respectively. The sensitivity of all other EIA kits across high quality studies ranged from 0% to 98.9% with median (IQR) = 90.6 [86.6, 95.2]; specificity ranged from 58.8% to 100.0% with median (IQR) = 100.0 [88.7, 100.0].ConclusionsEvidence on the diagnostic accuracy of currently available measles IgG EIAs is variable, insufficient, and may not be fit for purpose for serosurveillance goals. Additional studies evaluating the diagnostic accuracy of measles EIAs, including MBAs, should be conducted among diverse populations and settings (e.g., vaccination status, elimination/endemic status, age groups).

Contribution of Parvovirus B19 in Suspected Cases of Measles/Rubella in Osaka, Japan, between 2011 and 2021.

Erythema infectiosum, caused by human parvovirus B19 (B19V), is difficult to diagnose by its clinical symptoms and is often misdiagnosed as measles or rubella. Timely confirmation of measles/rubella or other viral etiologies via laboratory tests can provide an accurate picture of the infection status, which can appropriate response. The purpose of this study was to determine the contribution of B19V as an etiological agent for fever-rash in suspected cases of measles and rubella in Osaka Prefecture between 2011 and 2021. Of 1356 suspected cases, 167 were confirmed with measles and 166 with rubella using nucleic acid testing (NAT). Of the remaining 1023 cases, 970 from which blood specimens could be obtained were screened by real-time PCR for B19V, from which 136 (14%) tested positive. Of the positives cases, 21% were young children (9 years and younger), while 64% were adults (20 years and older). Phylogenetic tree analysis showed that 93 samples belonged to genotype 1a. The importance of B19V in the etiology of fever-rash illness was revealed in this study. The importance of laboratory diagnosis by NAT in maintaining the status of measles elimination and to eliminate rubella was reaffirmed. This article is protected by copyright. All rights reserved.

Vaccine Decision-making in a Time of Conflicting Recommendations: A Call to Go Beyond Politics.

Vaccine Decision-making in a Time of Conflicting Recommendations: A Call to Go Beyond Politics.

Increasing seroprevalence but waning herd immunity against measles after elimination: Longitudinal seroepidemiology of measles in Osaka Prefecture, Japan, 2003–2020

Japan is one of the countries conducting longitudinal serosurveillance of vaccine-preventable diseases. We conducted surveillance of the local measles-specific antibody titer, calculated the effective reproduction number (Re), and compared data of four terms: term 1, 2003–2006 (before the introduction of the second shot of measles-containing vaccine); term 2, 2007–2010 (early term toward measles elimination); term 3, 2011–2014 (later term toward measles elimination); and term 4, 2015–2020 (after elimination of measles in Japan). Approximately 250 sera from volunteers aged 0 to ≥ 40 years were collected and examined for measles-specific IgG using the gelatin particle agglutination (PA) method annually from 2003 to 2020. Seroprevalence and the geometric mean of the PA antibody titer were examined by term. Re was calculated using the age-dependent proportion immune and contact matrix for each term. Of the 4,716 sera, 886 in term 1, 1,217 in term 2, 1,069 in term 3, and 1,544 in term 4 were collected. The seroprevalence gradually increased from term 1 (88.3% CI 86.0–90.3) to term 4 (95.7% CI 94.6–96.7), and the seroprevalence of term 1 was significantly lower than those of other terms (Fisher’s exact test, p < 0.001), with PA titer ≥ 16 as positive. By contrast, PA antibody titers significantly decreased from term 1 (median 1,024) to term 4 (median 256) (Mann–Whitney U test, p < 0.001). With the protection level (PA titer ≥ 128 and ≥ 256) as positive, Re gradually increased from term 1 (1.8 and 2.3) to term 4 (2.5 and 4.8, respectively). Waning levels of measles antibodies potentially increase the measles susceptibility in Osaka, Japan. This trend might imply a limitation of vaccine-induced immunity in the absence of a natural booster for wild strains after measles elimination. This study provides a cue for maintaining continuous measles elimination status in the future.

Vaccine Exemptions and the Risk of Continued Disease Outbreaks.

Vaccine Exemptions and the Risk of Continued Disease Outbreaks.

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.

Epidemiology of measles cases, vaccine effectiveness, and performance towards measles elimination in The Gambia.

IntroductionIn 2011, member states of the World Health Organization (WHO) Africa Regional Office (AFRO) resolved to eliminate Measles by 2020. Our study aims to assess The Gambia’s progress towards the set AFRO measles elimination target and highlight surveillance and immunisation gaps to better inform future measles prevention strategies.Material and methodsA retrospective review of measles surveillance data for the period 2011–2019, was extracted from The Gambia case-based measles surveillance database. WHO—UNICEF national coverage estimates were used for estimating national level MCV coverage. Measles post campaign coverage survey coverage estimates were used to estimate national measles campaign coverage.ResultsOne hundred and twenty-five of the 863 reported suspected cases were laboratory confirmed as measles cases. More than half (53.6%) of the confirmed cases have unknown vaccination status, 24% of cases were vaccinated, 52.8% of cases occurred among males, and 72.8% cases were among urban residents. The incidence of measles cases per million population was lowest (0) in 2011–2012 and highest in 2015 and 2016 (31 and 23 respectively). The indicator for surveillance sensitivity was met in all years except in 2016 and 2019. Children aged 5–9 years (Incidence Rate Ratio—IRR = 0.6) and residents of Central River region (IRR = 0.21) had lower measles risk whilst unvaccinated (Adjusted IRR = 5.95) and those with unknown vaccination status (IRR 2.21) had higher measles risk. Vaccine effectiveness was 89.5%.ConclusionThe Gambia’s quest to attain measles elimination status by 2020 has registered significant success but it is unlikely that all target indicators will be met. Vaccination has been very effective in preventing cases. There is variation in measles risk by health region, and it will be important to take it into account when designing prevention and control strategies. The quality of case investigations should be improved to enhance the quality of surveillance for decision making.

Political Will, Vaccines, and Community Immunity.

Political Will, Vaccines, and Community Immunity.

The Many Costs of Measles Outbreaks and Undervaccination: Why We Need to Invest in Public Health.

In 2018 and 2019, the United States weathered a resurgence of measles, with >1600 cases reported to the Centers for Disease Control and Prevention. Most of these cases were associated with large outbreaks in New York and a smaller outbreak in Washington.1 For the 2018–2019 school year, kindergarten coverage with two doses of the measles, mumps, and rubella vaccine was 94.7% nationwide, 97.2% in New York, and 90.8% in Washington.2 These recent outbreaks confirmed modeling studies revealing that localized pockets of undervaccination and higher vaccine exemption rates plus exposure to travel create fertile conditions for measles spread.3,4 In previous measles studies, the significant cost of public health response activities needed to control these preventable outbreaks have been quantified.5,6 In this issue of Pediatrics , Pike et al7 expand on previous outbreak assessments to present a comprehensive cost evaluation of the 2019 measles outbreak in Clark County, Washington. These authors include direct medical costs; economic consequences of lost productivity due to illness, quarantine, and caregiving; and public health response costs. The 2019 outbreak comprised … Address correspondence to Jessica R. Cataldi, MD, MSCS, Section of Pediatric Infectious Diseases, Department of Pediatrics, School of Medicine, Anschutz Medical Campus, University of Colorado, 13123 E 16th Ave, Box 055, Aurora, CO 80045. E-mail: jessica.cataldi{at}cuanschutz.edu

Measles surveillance in Canada, 2019.

The Public Health Agency of Canada (PHAC) has conducted enhanced measles surveillance since 1998, the year endemic measles transmission was eliminated in Canada. The objective of this annual national measles surveillance report is to provide an epidemiologic summary of measles activity reported in Canada for 2019 in order to provide evidence to support the continued verification of Canada's measles elimination status. Measles surveillance data are housed in the Canadian Measles and Rubella Surveillance System (CMRSS) database. Descriptive analyses of demographics and risk factors were performed. Outbreak characteristics were summarized and genotypic analyses conducted. Surveillance, laboratory and vaccine coverage data for 2019 were used to assess Canada's status against the Pan American Health Organization (PAHO) essential criteria for the verification of measles elimination. In 2019, 113 measles cases were reported in Canada (crude incidence rate of 3.0 cases per 1,000,000 population). Of these cases, 42 (37%) were imported into Canada, and of the imported cases, 12 (29%) resulted in further transmission. Infants younger than one year had the highest age-specific incidence rate at 13.1 cases per 1,000,000 population. Only 29% of cases had one or more documented doses of measles-containing vaccine. One-fifth (19%) of cases were hospitalized; no deaths were reported. Genotype information was available for 100% of outbreaks reported in 2019 and 90% of non-outbreak-related measles cases; of cases with genotype information available, 27% were B3 and 73% were D8. Despite meeting/partially meeting only three out of four of PAHO's essential criteria for measles elimination status, there is no evidence that endemic measles transmission has been reestablished in Canada.

Molecular Epidemiology of Measles in California, United States—2019

In 2019, the United States (US) experienced the highest number of measles importations and cases in the postelimination era. More than a quarter of imported cases entered the US through California. Measles surveillance efforts in California resulted in the identification of 26 importations, 6 outbreaks, and 72 cases in 2019. Only genotype B3 and D8 measles strains were detected. Genotype-specific differences were noted in the incidence of vaccine failures, hospitalizations, and severe complications among cases. A targeted whole genome sequencing approach provided higher-resolution discrimination between epidemiologically linked and sporadically introduced strains than conventional N450 sequencing. Our report underscores the importance of ensuring appropriate measles vaccination status, especially prior to international travel to measles-endemic regions, and highlights the value of a strong measles surveillance system in minimizing outbreaks and preserving measles elimination status in the US.

Is it or is it not? Lessons learned from a case of suspected vaccine-associated measles

Background: Measles is a highly infectious viral disease that can cause serious illness and complications. Despite Australia's measles elimination status declared in 2014, the risk of acquiring measles through importation by overseas travellers who are non-immune remains. Identifying wild-type measles in a female who was recently vaccinated with measles mumps rubella (MMR) is a challenge one metropolitan Public Health Unit (PHU) experienced. Case Description: In 2018, a metropolitan Sydney PHU was notified of a positive polymerase chain reaction (PCR) result for measles on a nasopharyngeal swab for a 32 y old female who had recently received an MMR-II vaccination seven days prior to developing symptoms of measles. The case had no known epidemiological link, no recent overseas travel and no contact with recent measles cases during her incubation period. The reference laboratory ran sequencing on the clinical specimen to distinguish between wild-strain and vaccine-type measles. The results of this were inconclusive, however given the recent vaccination and inconsistent clinical symptoms and no identified epidemiological link, a decision was made to re-run the genotyping, collect additional specimens for testing, and quarantine the case until a definitive result was obtained. Subsequently, sequencing and genotyping test results revealed that this indeed was a wild-type measles strain, genotype D8. Discussion: A change in the epidemiology of measles, especially in low incidence countries like Australia, means distinguishing between wild type and vaccine–associated measles has become a new challenge, but critical in implementing a timely public health response. The initial decision to classify this case as vaccine-associated measles was based on the clinical context, epidemiological risk and inconclusive sequencing results. The lack of an epidemiological link created confusion for public health staff when investigating this case. Conclusion: This case investigation and response has demonstrated the challenge for public health with non-typical presentations of wild-type measles, particularly in people who have received one MMR. The reflection of the public health management of this case has provided an opportunity to learn from this experience and can become a valuable teaching tool for public health professionals globally, particularly in low incidence measles countries.

Investigation and control of a measles outbreak at the Hong Kong Special Administrative Region International Airport, 2019.

IntroductionHong Kong Special Administrative Region SAR (China) achieved measles elimination status in 2016, and the incidence of measles infection had been low over the past few years. However, the Centre for Health Protection (CHP) at the Department of Health was notified on 22 March 2019 of an outbreak of three cases of measles infection among workers at the Hong Kong Special Administrative Region International Airport (HKIA).MethodsWe reviewed notifications of measles received by CHP from 1 January to 17 May 2019. We defined a confirmed case of measles as having laboratory evidence of measles infection. All confirmed cases among airport workers or those with epidemiological information suggesting they had been infected by contact with airport workers were included in the review. We described the epidemiological features and reviewed the control measures against the outbreak.ResultsWe identified 33 cases, 29 of which were among airport workers. They comprised 22 men and 11 women, aged 20–49 years (median 25 years). The majority of people with confirmed measles presented with fever and rash. All required hospitalization. None developed complications. Control measures, including enhanced environmental hygiene and improved ventilation at HKIA and vaccinations for the airport community, were implemented. Vaccinations were provided to 8501 eligible airport workers, and the outbreak was declared over on 17 May 2019.DiscussionEarly recognition of the outbreak and prompt control measures, especially targeted vaccination of the exposed population, effectively controlled the outbreak in just two weeks.

A Call to Action: Strengthening Vaccine Confidence in the United States.

* Abbreviation: CDC — : Centers for Disease Control and Prevention In the United States and around the world, measles (a serious, potentially fatal, and extremely contagious infection) was considered a disease of the past until recently. However, what was once old news is now making headlines again with a remarkably predictable storyline: when immunity to measles falls in a population, outbreaks soon follow. This scenario has unfolded in places such as Ukraine, the Philippines, Israel, and Samoa with devastating consequences.1 In 2019 alone, the United Kingdom and 3 other European countries lost measles elimination status in part because of vaccine hesitancy, or the delay in acceptance or the refusal of vaccination despite availability of vaccination services, which was named one of the top global public health threats by the World Health Organization. Amid this global measles resurgence, the United States experienced a chain reaction of measles cases imported into close-knit, undervaccinated communities (primarily by unvaccinated US residents carrying measles home from outbreaks abroad), leading to outbreaks across the country in 2018 and 2019. These outbreaks were fueled by targeted vaccine misinformation and resulted in the highest number of measles cases in almost 30 years, nearly costing the United States its measles elimination status.2 To protect our nation, we need to change this narrative. We must empower families, in all … Address correspondence to Sarah Mbaeyi, MD, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, Mail Stop H24-8, Atlanta, GA 30329. E-mail: smbaeyi{at}cdc.gov