RESUMEN
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.
Asunto(s)
Sarampión , Estados Unidos/epidemiología , Humanos , Lactante , Recién Nacido , Preescolar , Niño , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Sarampión/epidemiología , Sarampión/prevención & control , Virus del Sarampión , Vacunación , Cobertura de Vacunación , Brotes de Enfermedades , Ciudad de Nueva York , Vacuna contra el Sarampión-Parotiditis-RubéolaRESUMEN
Syndromic polymerase chain reaction (PCR) panels are used to test for pathogens that can cause rash illnesses, including measles. Rash illnesses have infectious and noninfectious causes, and approximately 5% of persons experience a rash 7-10 days after receipt of a measles, mumps, and rubella (MMR) vaccine. MMR vaccine includes live attenuated measles virus, which is detectable by PCR tests. No evidence exists of person-to-person transmission of measles vaccine virus, and illness does not typically result among immunocompetent persons. During September 2022-January 2023, the Tennessee Department of Health received two reports of measles detected by syndromic PCR panels. Both reports involved children (aged 1 and 6 years) without known risk factors for measles, who were evaluated for rash that occurred 11-13 days after routine MMR vaccination. After public health responses in Tennessee determined that both PCR panels had detected measles vaccine virus, six state health departments collaborated to assess the frequency and characteristics of persons receiving a positive measles PCR panel test result in the United States. Information was retrospectively collected from a commercial laboratory testing for measles in syndromic multiplex PCR panels. During May 2022-April 2023, among 1,548 syndromic PCR panels, 17 (1.1%) returned positive test results for measles virus. Among 14 persons who received a positive test result and for whom vaccination and case investigation information were available, all had received MMR vaccine a median of 12 days before specimen collection, and none had known risk factors for acquiring measles. All positive PCR results were attributed to detection of measles vaccine virus. Increased awareness among health care providers about potential measles detection by PCR after vaccination is needed. Any detection of measles virus by syndromic PCR testing should be immediately reported to public health agencies, which can use measles vaccination history and assessment of risk factors to determine the appropriate public health response. If a person recently received MMR vaccine and has no risk factors for acquiring measles, additional public health response is likely unnecessary.
Asunto(s)
Exantema , Sarampión , Paperas , Rubéola (Sarampión Alemán) , Niño , Humanos , Estados Unidos/epidemiología , Lactante , Vacuna contra el Sarampión-Parotiditis-Rubéola , Estudios Retrospectivos , Sarampión/diagnóstico , Sarampión/epidemiología , Sarampión/prevención & control , Virus del Sarampión/genética , Paperas/prevención & control , Vacunación , Tennessee/epidemiología , Reacción en Cadena de la Polimerasa , Rubéola (Sarampión Alemán)/prevención & control , Anticuerpos AntiviralesRESUMEN
BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
Asunto(s)
Epidemias , Sarampión , Número Básico de Reproducción , Brotes de Enfermedades , Humanos , Sarampión/epidemiología , Sarampión/prevención & control , Vacuna Antisarampión , Virus del Sarampión/genética , Estados Unidos/epidemiología , VacunaciónRESUMEN
On August 29, 2021, the United States government oversaw the emergent establishment of Operation Allies Welcome (OAW), led by the U.S. Department of Homeland Security (DHS) and implemented by the U.S. Department of Defense (DoD) and U.S. Department of State (DoS), to safely resettle U.S. citizens and Afghan nationals from Afghanistan to the United States. Evacuees were temporarily housed at several overseas locations in Europe and Asia* before being transported via military and charter flights through two U.S. international airports, and onward to eight U.S. military bases, with hotel A used for isolation and quarantine of persons with or exposed to certain infectious diseases.§ On August 30, CDC issued an Epi-X notice encouraging public health officials to maintain vigilance for measles among Afghan evacuees because of an ongoing measles outbreak in Afghanistan (25,988 clinical cases reported nationwide during January-November 2021) (1) and low routine measles vaccination coverage (66% and 43% for the first and second doses, respectively, in 2020) (2).
Asunto(s)
Enfermedades Transmisibles , Sarampión , Enfermedades Transmisibles/epidemiología , Brotes de Enfermedades/prevención & control , Humanos , Sarampión/epidemiología , Sarampión/prevención & control , Salud Pública , Estados Unidos/epidemiología , VacunaciónRESUMEN
BACKGROUND: This paper highlights recent clinical complications of mumps reported in the United States and summarizes appropriate confirmatory testing for mumps, encouraging vigilance for mumps disease, an endemic vaccine-preventable illness. METHODS: Surveillance data from jurisdictions reporting confirmed and probable cases of mumps in the United States were descriptively analyzed to assess epidemiologic trends from January 1, 2018 - December 31, 2023. Data were reported to the National Notifiable Disease Surveillance System and the Epidemiology and Laboratory Capacity Project O. Cases were classified according to the Council of State and Territorial Epidemiologists 2011 mumps case definition. RESULTS: From 2018-2023, United States health departments reported 8,006 confirmed and probable mumps cases to the National Notifiable Disease Surveillance System, of which 85.4% occurred during January 1, 2018-April 4, 2020 and 14.6% during April 5, 2020-December 31, 2023. The incidence of mumps was highest among those aged 18-24 years during 2018-2020 (maximum of 4.54 cases per 100,000 persons in 2019), and highest among those aged 1-4 years during 2021-2023 (maximum 0.67 per 100,000 persons in 2023). Incidence among all age groups during 2021-2023 remained below levels during 2018-2020. Fewer than 12% of mumps cases were confirmed during 2021-2023, compared to >50% during 2018-2019. CONCLUSIONS: Although incidence has declined since the COVID-19 pandemic, these surveillance data highlight that mumps remains endemic in the United States. Therefore, maintaining high MMR vaccination coverage is essential to prevent future vaccine-preventable outbreaks and minimize severe complications from infection.
RESUMEN
Measles and rubella are vaccine-preventable viral diseases and can be prevented by safe, highly effective vaccination with measles- and rubella-containing vaccines. Given the myriad causes of febrile exanthems, laboratory surveillance for both measles and rubella is important to document the incidence of these diseases and to track the progress and maintenance of elimination in near- and post-elimination settings. Diagnostic challenges can hinder effective surveillance and classification challenges can hinder efforts to demonstrate achievement or maintenance of elimination. In this report, we review diagnostic and classification challenges for measles and rubella in near- and post-elimination settings.
RESUMEN
BACKGROUND: On Aug 29, 2021, Operation Allies Welcome (OAW) was established to support the resettlement of more than 80â000 Afghan evacuees in the USA. After identification of measles among evacuees, incoming evacuee flights were temporarily paused, and mass measles vaccination of evacuees aged 6 months or older was introduced domestically and overseas, with a 21-day quarantine period after vaccination. We aimed to evaluate patterns of measles virus transmission during this outbreak and the impact of control measures. METHODS: We conducted a measles outbreak investigation among Afghan evacuees who were resettled in the USA as part of OAW. Patients with measles were defined as individuals with an acute febrile rash illness between Aug 29, 2021, and Nov 26, 2021, and either laboratory confirmation of infection or epidemiological link to a patient with measles with laboratory confirmation. We analysed the demographics and clinical characteristics of patients with measles and used epidemiological information and whole-genome sequencing to track transmission pathways. A transmission model was used to evaluate the effects of vaccination and other interventions. FINDINGS: 47 people with measles (attack rate: 0·65 per 1000 evacuees) were reported in six US locations housing evacuees in four states. The median age of patients was 1 year (range 0-26); 33 (70%) were younger than 5 years. The age distribution shifted during the outbreak towards infants younger than 12 months. 20 (43%) patients with wild-type measles virus had rash onset after vaccination. No fatalities or community spread were identified, nor further importations after flight resumption. In a non-intervention scenario, transmission models estimated that a median of 5506 cases (IQR 10-5626) could have occurred. Infection clusters based on epidemiological criteria could be delineated into smaller clusters using phylogenetic analyses; however, sequences with few substitution count differences did not always indicate single lines of transmission. INTERPRETATION: Implementation of control measures limited measles transmission during OAW. Our findings highlight the importance of integration between epidemiological and genetic information in discerning between individual lines of transmission in an elimination setting. FUNDING: US Centers for Disease Control and Prevention.
Asunto(s)
Exantema , Sarampión , Lactante , Humanos , Virus del Sarampión/genética , Salud Pública , Filogenia , Sarampión/epidemiología , Sarampión/prevención & control , Estudios EpidemiológicosRESUMEN
Using a coronavirus disease 2019 (COVID-19)-associated hospitalization surveillance network, we found that 42.5% of hospitalized COVID-19 cases with available data from March 1-June 30, 2020, received ≥1 COVID-19 investigational treatment. Hydroxychloroquine, azithromycin, and remdesivir were used frequently; however, hydroxychloroquine and azithromycin use declined over time, while use of remdesivir increased.