RESUMO
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.
Assuntos
Epidemias , Sarampo , Número Básico de Reprodução , Surtos de Doenças , Humanos , Sarampo/epidemiologia , Sarampo/prevenção & controle , Vacina contra Sarampo , Vírus do Sarampo/genética , Estados Unidos/epidemiologia , VacinaçãoRESUMO
BACKGROUND: Mumps is an acute viral illness that classically presents with parotitis. Although the United States experienced a 99% reduction in mumps cases following implementation of the 2-dose vaccination program in 1989, mumps has resurged in the past 10 years. METHODS: We assessed the epidemiological characteristics of mumps outbreaks with ≥20 cases reported in the United States electronically through the National Notifiable Diseases Surveillance System and from supplemental outbreak data through direct communications with jurisdictions from July 2010 through December 2015. Mumps cases were defined using the 2012 Council of State and Territorial Epidemiologists case definition. RESULTS: Twenty-three outbreaks with 20-485 cases per outbreak were reported in 18 jurisdictions. The duration of outbreaks ranged from 1.5 to 8.5 months (median, 3 months). All outbreaks involved close-contact settings; 18 (78%) involved universities, 16 (70%) occurred primarily among young adults (median age, 18-24 years), and 9 (39%) occurred in highly vaccinated populations (2-dose measles-mumps-rubella vaccine coverage ≥85%). CONCLUSIONS: During 2010-2015, multiple mumps outbreaks among highly vaccinated populations in close-contact settings occurred. Most cases occurred among vaccinated young adults, suggesting that waning immunity played a role. Further evaluation of risk factors associated with these outbreaks is warranted.
Assuntos
Surtos de Doenças/estatística & dados numéricos , Monitoramento Epidemiológico , Programas de Imunização , Vacina contra Sarampo-Caxumba-Rubéola/administração & dosagem , Caxumba/epidemiologia , Vacinação/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Humanos , Lactente , Pessoa de Meia-Idade , Caxumba/transmissão , Pesquisa Qualitativa , Fatores de Risco , Estudantes/estatística & dados numéricos , Estados Unidos/epidemiologia , Universidades , Adulto JovemRESUMO
BACKGROUND: Although measles was eliminated in the United States in 2000, importations of the virus continue to cause outbreaks. We describe the epidemiologic features of an outbreak of measles that originated from two unvaccinated Amish men in whom measles was incubating at the time of their return to the United States from the Philippines and explore the effect of public health responses on limiting the spread of measles. METHODS: We performed descriptive analyses of data on demographic characteristics, clinical and laboratory evaluations, and vaccination coverage. RESULTS: From March 24, 2014, through July 23, 2014, a total of 383 outbreak-related cases of measles were reported in nine counties in Ohio. The median age of case patients was 15 years (range, <1 to 53); a total of 178 of the case patients (46%) were female, and 340 (89%) were unvaccinated. Transmission took place primarily within households (68% of cases). The virus strain was genotype D9, which was circulating in the Philippines at the time of the reporting period. Measles-mumps-rubella (MMR) vaccination coverage with at least a single dose was estimated to be 14% in affected Amish households and more than 88% in the general (non-Amish) Ohio community. Containment efforts included isolation of case patients, quarantine of susceptible persons, and administration of the MMR vaccine to more than 10,000 persons. The spread of measles was limited almost exclusively to the Amish community (accounting for 99% of case patients) and affected only approximately 1% of the estimated 32,630 Amish persons in the settlement. CONCLUSIONS: The key epidemiologic features of a measles outbreak in the Amish community in Ohio were transmission primarily within households, the small proportion of Amish people affected, and the large number of people in the Amish community who sought vaccination. As a result of targeted containment efforts, and high baseline coverage in the general community, there was limited spread beyond the Amish community. (Funded by the Ohio Department of Health and the Centers for Disease Control and Prevention.).
Assuntos
Amish/estatística & dados numéricos , Surtos de Doenças , Vacina contra Sarampo-Caxumba-Rubéola/administração & dosagem , Sarampo/epidemiologia , Vacinação/estatística & dados numéricos , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Sarampo/transmissão , Pessoa de Meia-Idade , Ohio/epidemiologiaRESUMO
As of April 26, 2019, CDC had reported 704 cases of measles in the United States since the beginning of 2019, representing the largest number of cases reported in the country in a single year since 1994, when 963 cases occurred, and since measles was declared eliminated* in 2000 (1,2). Measles is a highly contagious, acute viral illness characterized by fever and a maculopapular rash; complications include pneumonia, encephalitis, and death. Among the 704 cases, 503 (71%) were in unvaccinated persons and 689 (98%) occurred in U.S. residents. Overall, 66 (9%) patients were hospitalized. Thirteen outbreaks have been reported in 2019, accounting for 663 cases, 94% of all reported cases. Six of the 13 outbreaks were associated with underimmunized close-knit communities and accounted for 88% of all cases. High 2-dose measles vaccination coverage in the United States has been critical to limiting transmission (3). However, increased global measles activity poses a risk to U.S. elimination, particularly when unvaccinated travelers acquire measles abroad and return to communities with low vaccination rates (4). Health care providers should ensure persons are up to date with measles, mumps, rubella (MMR) vaccine, including before international travel, and rapidly report all suspected cases of measles to public health authorities.
Assuntos
Surtos de Doenças , Sarampo/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Erradicação de Doenças , Humanos , Incidência , Lactente , Internacionalidade , Sarampo/prevenção & controle , Vacina contra Sarampo-Caxumba-Rubéola/administração & dosagem , Pessoa de Meia-Idade , Risco , Doença Relacionada a Viagens , Estados Unidos/epidemiologia , Vacinação/estatística & dados numéricos , Adulto JovemRESUMO
During January 1-October 1, 2019, a total of 1,249 measles cases and 22 measles outbreaks were reported in the United States. This represents the most U.S. cases reported in a single year since 1992 (1), and the second highest number of reported outbreaks annually since measles was declared eliminated* in the United States in 2000 (2). Measles is an acute febrile rash illness with an attack rate of approximately 90% in susceptible household contacts (3). Domestic outbreaks can occur when travelers contract measles outside the United States and subsequently transmit infection to unvaccinated persons they expose in the United States. Among the 1,249 measles cases reported in 2019, 1,163 (93%) were associated with the 22 outbreaks, 1,107 (89%) were in patients who were unvaccinated or had an unknown vaccination status, and 119 (10%) measles patients were hospitalized. Closely related outbreaks in New York City (NYC) and New York State (NYS; excluding NYC), with ongoing transmission for nearly 1 year in large and close-knit Orthodox Jewish communities, accounted for 934 (75%) cases during 2019 and threatened the elimination status of measles in the United States. Robust responses in NYC and NYS were effective in controlling transmission before the 1-year mark; however, continued vigilance for additional cases within these communities is essential to determine whether elimination has been sustained. Collaboration between public health authorities and undervaccinated communities is important for preventing outbreaks and limiting transmission. The combination of maintenance of high national vaccination coverage with measles, mumps, and rubella vaccine (MMR) and rapid implementation of measles control measures remains the cornerstone for preventing widespread measles transmission (4).
Assuntos
Surtos de Doenças/estatística & dados numéricos , Sarampo/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Sarampo/prevenção & controle , Vacina contra Sarampo-Caxumba-Rubéola/administração & dosagem , Pessoa de Meia-Idade , Estados Unidos/epidemiologia , Vacinação/estatística & dados numéricos , Adulto JovemRESUMO
We assessed the status of measles elimination in the United States using outbreak notification data. Measles transmissibility was assessed by estimation of the reproduction number, R, the average number of secondary cases per infection, using 4 methods; elimination requires maintaining R at <1. Method 1 estimates R as 1 minus the proportion of cases that are imported. Methods 2 and 3 estimate R by fitting a model of the spread of infection to data on the sizes and generations of chains of transmission, respectively. Method 4 assesses transmissibility before public health interventions, by estimating R for the case with the earliest symptom onset in each cluster (Rindex). During 2001-2014, R and Rindex estimates obtained using methods 1-4 were 0.72 (95% confidence interval (CI): 0.68, 0.76), 0.66 (95% CI: 0.62, 0.70), 0.45 (95% CI: 0.40, 0.49), and 0.63 (95% CI: 0.57, 0.69), respectively. Year-to-year variability in the values of R and Rindex and an increase in transmissibility in recent years were noted with all methods. Elimination of endemic measles transmission is maintained in the United States. A suggested increase in measles transmissibility since elimination warrants continued monitoring and emphasizes the importance of high measles vaccination coverage throughout the population.
Assuntos
Erradicação de Doenças/estatística & dados numéricos , Sarampo/prevenção & controle , Adolescente , Criança , Pré-Escolar , Erradicação de Doenças/métodos , Surtos de Doenças/prevenção & controle , Surtos de Doenças/estatística & dados numéricos , Humanos , Programas de Imunização , Lactente , Sarampo/epidemiologia , Sarampo/transmissão , Vacina contra Sarampo/uso terapêutico , Estados Unidos/epidemiologiaRESUMO
Between 2001 and 2014, 78 reported measles cases resulted from transmission in US healthcare facilities, and 29 healthcare personnel were infected from occupational exposure, 1 of whom transmitted measles to a patient. The economic impact of preventing and controlling measles transmission in healthcare facilities was $19 000-$114 286 per case.
Assuntos
Infecção Hospitalar/epidemiologia , Sarampo/epidemiologia , Controle de Doenças Transmissíveis/economia , Controle de Doenças Transmissíveis/métodos , Infecção Hospitalar/transmissão , Transmissão de Doença Infecciosa , Custos de Cuidados de Saúde , Instalações de Saúde , Humanos , Sarampo/transmissão , Exposição Ocupacional , Estados Unidos/epidemiologiaRESUMO
Measles is a highly contagious, acute viral illness that can lead to complications such as pneumonia, encephalitis, and death. As a result of high 2-dose measles vaccination coverage in the United States and improved control of measles in the World Health Organization's Region of the Americas, the United States declared measles elimination (defined as interruption of year-round endemic transmission) in 2000. Importations from other countries where measles remains endemic continue to occur, however, which can lead to clusters of measles cases in the United States. To update surveillance data on current measles outbreaks, CDC analyzed cases reported during January 4-April 2, 2015. A total of 159 cases were reported during this period. Over 80% of the cases occurred among persons who were unvaccinated or had unknown vaccination status. Four outbreaks have occurred, with one accounting for 70% of all measles cases this year. The continued risk for importation of measles into the United States and occurrence of measles cases and outbreaks in communities with high proportions of unvaccinated persons highlight the need for sustained, high vaccination coverage across the country.
Assuntos
Surtos de Doenças , Sarampo/epidemiologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Humanos , Lactente , Sarampo/prevenção & controle , Vacina contra Sarampo-Caxumba-Rubéola/administração & dosagem , Pessoa de Meia-Idade , Viagem , Estados Unidos/epidemiologia , Vacinação/estatística & dados numéricos , Adulto JovemAssuntos
Viagem Aérea , Surtos de Doenças , Internacionalidade , Sarampo/epidemiologia , Doença Relacionada a Viagens , Adolescente , Adulto , California/epidemiologia , Criança , Busca de Comunicante , Humanos , Vírus do Sarampo/genética , Vírus do Sarampo/isolamento & purificação , Reação em Cadeia da PolimeraseRESUMO
Measles is a highly contagious, acute viral illness that can lead to serious complications and death. Although measles elimination (i.e., interruption of year-round endemic transmission) was declared in the United States in 2000, importations of measles cases from endemic areas of the world continue to occur, leading to secondary measles cases and outbreaks in the United States, primarily among unvaccinated persons. To update national measles data in the United States, CDC evaluated cases reported by states from January 1 through May 23, 2014. A total of 288 confirmed measles cases have been reported to CDC, surpassing the highest reported yearly total of measles cases since elimination (220 cases reported in 2011). Fifteen outbreaks accounted for 79% of cases reported, including the largest outbreak reported in the United States since elimination (138 cases and ongoing). The large number of cases this year emphasizes the need for health-care providers to have a heightened awareness of the potential for measles in their communities and the importance of vaccination to prevent measles.
Assuntos
Surtos de Doenças , Sarampo/epidemiologia , Adolescente , Adulto , Idoso , Centers for Disease Control and Prevention, U.S. , Criança , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Sarampo/prevenção & controle , Vacina contra Sarampo/administração & dosagem , Pessoa de Meia-Idade , Risco , Viagem , Estados Unidos/epidemiologia , Vacinação/estatística & dados numéricos , Adulto JovemRESUMO
On 29 October 2004, an expert panel was convened to review the status of elimination of rubella and congenital rubella syndrome (CRS) in the United States. Primarily based on 5 types of information presented--epidemiology of reported cases, molecular epidemiology, seroprevalence, vaccine coverage, and adequacy of surveillance--the panel unanimously agreed that rubella virus is no longer endemic in the United States. Since 2004, new data continue to support the conclusion that elimination has been achieved and maintained. In documenting elimination in the United States, each of the 5 types of data provided evidence for elimination and collectively provided much stronger evidence than any one type could individually. As countries document the elimination of rubella and CRS, many sources and types of data will likely be necessary. Rigorous data evaluation must be conducted to look for inconsistencies among the available data. To maintain elimination, countries should maintain high vaccine coverage, adequate surveillance, and rapid response to outbreaks.
Assuntos
Controle de Doenças Transmissíveis/métodos , Síndrome da Rubéola Congênita/epidemiologia , Síndrome da Rubéola Congênita/prevenção & controle , Vacina contra Rubéola/imunologia , Adolescente , Adulto , Criança , Pré-Escolar , Surtos de Doenças , Emigrantes e Imigrantes , Genótipo , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-Idade , Epidemiologia Molecular , Vigilância da População , Vacina contra Rubéola/administração & dosagem , Vírus da Rubéola/genética , Estados Unidos/epidemiologia , Adulto JovemRESUMO
BACKGROUND: The widespread use of a second dose of mumps vaccine among U.S. schoolchildren beginning in 1990 was followed by historically low reports of mumps cases. A 2010 elimination goal was established, but in 2006 the largest mumps outbreak in two decades occurred in the United States. METHODS: We examined national data on mumps cases reported during 2006, detailed case data from the most highly affected states, and vaccination-coverage data from three nationwide surveys. RESULTS: A total of 6584 cases of mumps were reported in 2006, with 76% occurring between March and May. There were 85 hospitalizations, but no deaths were reported; 85% of patients lived in eight contiguous midwestern states. The national incidence of mumps was 2.2 per 100,000, with the highest incidence among persons 18 to 24 years of age (an incidence 3.7 times that of all other age groups combined). In a subgroup analysis, 83% of these patients reported current college attendance. Among patients in eight highly affected states with known vaccination status, 63% overall and 84% between the ages of 18 and 24 years had received two doses of mumps vaccine. For the 12 years preceding the outbreak, national coverage of one-dose mumps vaccination among preschoolers was 89% or more nationwide and 86% or more in highly affected states. In 2006, the national two-dose coverage among adolescents was 87%, the highest in U.S. history. CONCLUSIONS: Despite a high coverage rate with two doses of mumps-containing vaccine, a large mumps outbreak occurred, characterized by two-dose vaccine failure, particularly among midwestern college-age adults who probably received the second dose as schoolchildren. A more effective mumps vaccine or changes in vaccine policy may be needed to avert future outbreaks and achieve the elimination of mumps.
Assuntos
Vacina contra Caxumba , Caxumba/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Criança , Pré-Escolar , Feminino , Humanos , Imunização Secundária , Lactente , Masculino , Pessoa de Meia-Idade , Vacina contra Caxumba/administração & dosagem , Vírus da Caxumba/genética , Vírus da Caxumba/isolamento & purificação , Reação em Cadeia da Polimerase , Falha de Tratamento , Estados Unidos/epidemiologia , Vacinação/estatística & dados numéricosRESUMO
BACKGROUND: Measles affected entire birth cohorts in the prevaccine era but was declared eliminated in the United States in 2000 because of a successful measles vaccination program. METHODS: We reviewed US surveillance data on confirmed measles cases reported to the Centers for Disease Control and Prevention and data on national measles-mumps-rubella (MMR) vaccination coverage during postelimination years 2001-2008. RESULTS: During 2001-2008, a total of 557 confirmed cases of measles (annual median no. of cases, 56) and 38 outbreaks (annual median no. of outbreaks, 4) were reported in the United States; 232 (42%) of the cases were imported from 44 countries, including European countries. Among case-patients who were US residents, the highest incidences of measles were among infants 6-11 months of age and children 12-15 months of age (3.5 and 2.6 cases/1 million person-years, respectively). From 2001 through 2008, national 1-dose MMR vaccine coverage among children 19-35 months of age ranged from 91% to 93%. From 2001 through 2008, a total of 285 US-resident case-patients (65%) were considered to have preventable measles (ie, the patients were eligible for vaccination but unvaccinated). During 2004-2008, a total of 68% of vaccine-eligible US-resident case-patients claimed exemptions for personal beliefs. CONCLUSIONS: The United States maintained measles elimination from 2001 through 2008 because of sustained high vaccination coverage. Challenges to maintaining elimination include large outbreaks of measles in highly traveled developed countries, frequent international travel, and clusters of US residents who remain unvaccinated because of personal belief exemptions.
Assuntos
Surtos de Doenças , Vacina contra Sarampo-Caxumba-Rubéola/administração & dosagem , Sarampo/epidemiologia , Sarampo/imunologia , Vacinação , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Masculino , Fatores de Risco , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: Measles, a vaccine-preventable disease that can cause severe complications, was declared eliminated from the United States in 2000. The last published summary of US measles epidemiology was during 2001-2008. We summarized US measles epidemiology during 2009-2014. METHODS: We compared demographic, vaccination, and virologic data on confirmed measles cases reported to the Centers for Disease Control and Prevention during January 1, 2009-December 31, 2014 and January 1, 2001-December 31, 2008. RESULTS: During 2009-2014, 1264 confirmed measles cases were reported in the United States, including 275 importations from 58 countries and 66 outbreaks. The annual median number of cases and outbreaks during this period was 130 (range, 55-667 cases) and 10 (range, 4-23 outbreaks), respectively, compared with an annual median of 56 cases (P = .08) and 4 outbreaks during 2001-2008 (P = .04). Among US-resident case-patients during 2009-2014, children aged 12-15 months had the highest measles incidence (65 cases; 8.3 cases/million person-years), and infants aged 6-11 months had the second highest incidence (86 cases; 7.3 cases/million person-years). During 2009-2014, 865 (74%) of 1173 US-resident case-patients were unvaccinated and 188 (16%) had unknown vaccination status; of 917 vaccine-eligible US-resident case-patients, 600 (65%) were reported as having philosophical or religious objections to vaccination. CONCLUSIONS: Although the United States has maintained measles elimination since 2000, measles outbreaks continue to occur globally, resulting in imported cases and potential spread. The annual median number of cases and outbreaks more than doubled during 2009-2014 compared with the earlier postelimination years. To maintain elimination, it will be necessary to maintain high 2-dose vaccination coverage, continue case-based surveillance, and monitor the patterns and rates of vaccine exemption.
Assuntos
Erradicação de Doenças , Sarampo/epidemiologia , Sarampo/prevenção & controle , Fatores Etários , Estudos Transversais , Surtos de Doenças/estatística & dados numéricos , Feminino , Humanos , Programas de Imunização , Esquemas de Imunização , Incidência , Lactente , Masculino , Vacina contra Sarampo/administração & dosagem , Vigilância da População , Estados Unidos , Cobertura Vacinal/estatística & dados numéricosRESUMO
In 1969, the United States established its national rubella vaccination program. With the success of the program, 32 years later, reports of rubella reached record low numbers. To assess the achievement of elimination of rubella and congenital rubella syndrome (CRS) in the United States, 7 epidemiological criteria were used. Rubella cases reported to the National Notifiable Diseases Surveillance System from 1998 through 2004 and CRS cases reported to the National Congenital Rubella Syndrome Registry from 1998 through 2004 were analyzed. During 1998-2000, the median number of reported rubella cases was 272, whereas, during 2001-2004, the median number reported was 13. The incidence of rubella decreased significantly, from 0.1/100,000 population in 1998 to 0.005/100,000 population in 2004. Since 2001, 5 infants with CRS have been reported--3 were born in 2001, 1 was born in 2003, and 1 was born in 2004. The epidemiological evidence strongly supports the claim that rubella is no longer endemic in the United States. To prevent future rubella outbreaks and CRS cases, current strategies must be maintained.
Assuntos
Síndrome da Rubéola Congênita/epidemiologia , Síndrome da Rubéola Congênita/transmissão , Rubéola (Sarampo Alemão)/epidemiologia , Rubéola (Sarampo Alemão)/transmissão , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: Reported rubella cases in the United States are at the lowest numbers since the introduction of vaccine, suggesting that endemic transmission may have been interrupted. It is necessary to validate that the observed absence of rubella is due to the disappearance of disease rather than a failure of rubella surveillance. METHODS: Adequate rubella surveillance to detect ongoing transmission is characterized by evidence that rubella investigations are being conducted, detection of importations, and lack of spread from confirmed cases. We reviewed rubella surveillance data and activities from 5 sources: (1) data reported to the national surveillance system; (2) a survey of health departments and public health laboratories, including questions regarding any links between measles and rubella surveillance; (3) enhanced rubella surveillance activities in California and in New York City; (4) sentinel surveillance along the US-Mexico border; and (5) case detection in 8 large health maintenance organizations (HMOs). RESULTS: During 2002-2004, 35 cases of rubella were reported to the national system, including 12 (34%) imported cases. The 39 programs that responded to our survey reported conducting 1482 investigations for rubella; according to another national survey, 1921 investigations were conducted for measles. Forty-one laboratories responded to our survey and reported conducting 6428 tests for acute rubella. No previously undetected (or unreported) cases of rubella or congenital rubella syndrome were identified by our survey or reviews of surveillance in California, New York, and along the US-Mexico border, and no additional cases were detected in the HMO database. CONCLUSIONS: No previously unrecognized spread cases or outbreaks of rubella were detected. Surveillance in the United States is sufficiently sensitive to identify indigenous cases of rubella, if they were occurring, supporting the contention that rubella has been eliminated from the United States.
Assuntos
Vigilância da População/métodos , Rubéola (Sarampo Alemão)/diagnóstico , Rubéola (Sarampo Alemão)/transmissão , Notificação de Doenças , Surtos de Doenças , Humanos , Programas Nacionais de Saúde , Rubéola (Sarampo Alemão)/epidemiologia , Estados Unidos/epidemiologiaRESUMO
In the United States, approximately 9% of the measles cases reported from 2012 to 2014 occurred in vaccinated individuals. Laboratory confirmation of measles in vaccinated individuals is challenging since IgM assays can give inconclusive results. Although a positive reverse transcription (RT)-PCR assay result from an appropriately timed specimen can provide confirmation, negative results may not rule out a highly suspicious case. Detection of high-avidity measles IgG in serum samples provides laboratory evidence of a past immunologic response to measles from natural infection or immunization. High concentrations of measles neutralizing antibody have been observed by plaque reduction neutralization (PRN) assays among confirmed measles cases with high-avidity IgG, referred to here as reinfection cases (RICs). In this study, we evaluated the utility of measuring levels of measles neutralizing antibody to distinguish RICs from noncases by receiver operating characteristic curve analysis. Single and paired serum samples with high-avidity measles IgG from suspected measles cases submitted to the CDC for routine surveillance were used for the analysis. The RICs were confirmed by a 4-fold rise in PRN titer or by RT-quantitative PCR (RT-qPCR) assay, while the noncases were negative by both assays. Discrimination accuracy was high with serum samples collected ≥3 days after rash onset (area under the curve, 0.953; 95% confidence interval [CI], 0.854 to 0.993). Measles neutralizing antibody concentrations of ≥40,000 mIU/ml identified RICs with 90% sensitivity (95% CI, 74 to 98%) and 100% specificity (95% CI, 82 to 100%). Therefore, when serological or RT-qPCR results are unavailable or inconclusive, suspected measles cases with high-avidity measles IgG can be confirmed as RICs by measles neutralizing antibody concentrations of ≥40,000 mIU/ml.
Assuntos
Anticorpos Neutralizantes/sangue , Afinidade de Anticorpos , Testes Diagnósticos de Rotina/métodos , Imunoglobulina G/sangue , Vírus do Sarampo/imunologia , Sarampo/diagnóstico , Testes de Neutralização/métodos , Adolescente , Adulto , Idoso , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Sarampo/imunologia , Pessoa de Meia-Idade , Recidiva , Sensibilidade e Especificidade , Estados Unidos , Adulto JovemRESUMO
IMPORTANCE: To verify the elimination of endemic measles, rubella, and congenital rubella syndrome (CRS) from the Western hemisphere, the Pan American Health Organization requested each member country to compile a national elimination report. The United States documented the elimination of endemic measles in 2000 and of endemic rubella and CRS in 2004. In December 2011, the Centers for Disease Control and Prevention convened an external expert panel to review the evidence and determine whether elimination of endemic measles, rubella, and CRS had been sustained. OBJECTIVE: To review the evidence for sustained elimination of endemic measles, rubella, and CRS from the United States through 2011. DESIGN, SETTING, AND PARTICIPANTS: Review of data for measles from 2001 to 2011 and for rubella and CRS from 2004 to 2011 covering the US resident population and international visitors, including disease epidemiology, importation status of cases, molecular epidemiology, adequacy of surveillance, and population immunity as estimated by national vaccination coverage and serologic surveys. MAIN OUTCOMES AND MEASURES: Annual numbers of measles, rubella, and CRS cases, by importation status, outbreak size, and distribution; proportions of US population seropositive for measles and rubella; and measles-mumps-rubella vaccination coverage levels. RESULTS: Since 2001, US reported measles incidence has remained below 1 case per 1,000,000 population. Since 2004, rubella incidence has been below 1 case per 10,000,000 population, and CRS incidence has been below 1 case per 5,000,000 births. Eighty-eight percent of measles cases and 54% of rubella cases were internationally imported or epidemiologically or virologically linked to importation. The few cases not linked to importation were insufficient to represent endemic transmission. Molecular epidemiology indicated no endemic genotypes. The US surveillance system is adequate to detect endemic measles or rubella. Seroprevalence and vaccination coverage data indicate high levels of population immunity to measles and rubella. CONCLUSIONS AND RELEVANCE: The external expert panel concluded that the elimination of endemic measles, rubella, and CRS from the United States was sustained through 2011. However, international importation continues, and health care providers should suspect measles or rubella in patients with febrile rash illness, especially when associated with international travel or international visitors, and should report suspected cases to the local health department.
Assuntos
Doenças Endêmicas/estatística & dados numéricos , Sarampo/epidemiologia , Rubéola (Sarampo Alemão)/epidemiologia , Doenças Endêmicas/prevenção & controle , Monitoramento Epidemiológico , História do Século XXI , Humanos , Vacinação em Massa/estatística & dados numéricos , Sarampo/prevenção & controle , Vacina contra Sarampo-Caxumba-Rubéola , Rubéola (Sarampo Alemão)/prevenção & controle , Síndrome da Rubéola Congênita/epidemiologia , Síndrome da Rubéola Congênita/prevenção & controle , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: Flight-related measles contact investigations in the United States are coordinated by the Centers for Disease Control and Prevention (CDC). To evaluate the efficiency of CDC's measles protocol, we analyzed data from contact investigations conducted December 2008-December 2011. METHODS: Cases were defined as travelers diagnosed with measles that were infectious at the time of the flight. Passengers seated within 2 rows of the case-traveler and all babies-in-arms were defined as contacts. Contact information obtained from airlines was distributed to US health departments; reporting of outcomes was requested. We cross-referenced the National Notifiable Diseases Surveillance System and CDC's National Center for Immunization and Respiratory Diseases to identify unreported cases in passenger-contacts and in passengers not identified as contacts. RESULTS: Our evaluation included 74 case-travelers on 108 flights. Information for 2673 (79%) of 3399 passenger-contacts was provided to health departments; 9 cases of secondary measles were reported. No additional cases were identified. CONCLUSION: Our evaluation provided evidence of measles transmission related to air travel. CDC's protocol efficiently identifies passengers most at risk of exposure and infection for flights into and within the United States.