Outbreak of rubella after mass vaccination of children and adult women: challenges for rubella elimination strategies / Brote epidémico de rubéola tras la vacunación masiva de niños y mujeres adultas: un reto para las estrategias de eliminación de la rubéola

OBJECTIVE: To describe rubella outbreaks and control strategies in the Brazilian state of Rio Grande do Sul before rubella elimination. METHODS: We analyzed rubella and congenital rubella syndrome surveillance data for the state of Rio Grande do Sul and calculated age- and gender-specific incidence of confirmed rubella cases in 2007. We obtained data on measles-rubella doses administered during the outbreak from the state immunization program and reviewed the timing of suspect case notification and implementation of control measures. RESULTS: Of 2 842 confirmed rubella cases reported to the state health department in 2007, 2 145 (75.5 percent) were in males (39.5 cases per 100 000 population) and 697 (24.5 percent) were in females (12.3 per 100 000 population). Incidence among 15- to 39-year-olds was 1.8 to 5.5 times higher in males than in females. Rubella genotype 2B was detected in nasopharyngeal specimens from 13 patients from multiple chains of transmission. Eight children were born with congenital rubella syndrome (5.9 cases per 100 000 births in 2008). Delayed notification of initial cases hampered early control efforts, resulting in outbreak spread throughout the state. Rubella transmission was interrupted after mass vaccination of adult men and women as part of a national vaccination campaign. CONCLUSIONS: Routine vaccination strategies and mass vaccination of adolescents and adults for accelerated rubella control and elimination should target men and women.

OBJETIVO: Describir los brotes de rubéola y las estrategias para el control de la enfermedad anteriores a la eliminación de la rubéola en el estado brasileño de Rio Grande do Sul. MÉTODOS: Se analizaron los datos de vigilancia epidemiológica sobre la rubéola y el síndrome de rubéola congénita del estado de Rio Grande do Sul y se calculó la incidencia específica por edad y sexo de los casos confirmados de rubéola en el 2007. A partir del programa de vacunación estatal se obtuvieron datos sobre las dosis de vacunación antisarampionosa y antirrubeólica administradas durante el brote y se analizaron el momento de notificación de los casos sospechosos y la puesta en práctica de medidas de control. RESULTADOS: De los 2842 casos confirmados de rubéola notificados al departamento de salud estatal en el 2007, 2 145 (75,5 por ciento) correspondieron a hombres (39,5 casos por 100000 habitantes) y 697 (24,5 por ciento) a mujeres (12,3 por 100000 habitantes). La incidencia en las personas de 15 a 39 años de edad fue de 1,8 a 5,5 veces mayor en los varones que en las mujeres. En 13 pacientes provenientes de distintas cadenas de transmisión se detectó el genotipo 2B del virus de la rubéola en muestras obtenidas de la nasofaringe. Nacieron 8 niños con síndrome de rubéola congénita (5,9 casos por 100000 nacimientos en el 2008). La demora en la notificación de los casos iniciales obstaculizó la adopción temprana de medidas de control, lo que hizo que el brote se propagara a todo el estado. La transmisión de la rubéola se interrumpió después de la vacunación masiva de varones y mujeres adultos como parte de una campaña nacional de vacunación. CONCLUSIONES: Las estrategias de vacunación sistemática y la vacunación masiva de adolescentes y adultos tendientes a acelerar el control y la eliminación de la rubéola deben dirigirse tanto a varones como a mujeres.

Avaliação prospectica de gestantes vacinadas contra rubéola no sul do Brasil / Prospective evaluation of pregnant women that received rubella vaccine in south

Objetivos: Avaliar a ocorrência de Síndrome da Rubéola Congênita em mulheres que foram vacinadas contra rubéola e que não sabiam que estavam grávidas, ou que engravidaram até 30 dias após a vacinação. Métodos: foram coletados, prospectivamente, dados de 171 gestantes que se encontravam suscetíveis no momento da vacinação. No momento do parto foi colhido sangue dos recém-nascidos para exames. Todos os bebês com IgM anti rubéola positiva foram clinicamente avaliados conforme protocolo para detecção de sequelas da síndrome da rubéola congênita. Foi realizada a coleta de secreção nasofaríngea para isolamento e identificação viral. Resultados: foi coletada amostra sorológica de 152 bebês, filhos de mãe suscetíveis. Um total de 10 bebês (6,3%) apresentou presença de anticorpos IgM anti-rubéola, ou seja, foram infectados pelo vírus vacinal durante a gestação. Nenhum deles apresentou defeitos congênitos relacionados à rubéola. Conclusões: o estudo permite ampliar a segurança da vacinação para rubéola em mulheres grávidas.

Prevalence of antibodies against measles, mumps, and rubella before and after vaccination of school-age children with three different triple combined viral vaccines, Rio Grande do Sul, Brazil, 1996

OBJECTIVE: We evaluated the seroprevalence for measles, mumps, and rubella in school-age children (6-12 years old) before and after the administration of three triple combined viral vaccines. METHODS: In two municipal schools of Rio Grande do Sul, Brazil, 692 blood samples were collected before vaccination and 636 samples 21 to 30 days after vaccination during 1996. IgG antibody seropositivity was investigated by enzyme-linked immunosorbent assay (measles and mumps with Enzygnost [Behring, Marburg, Germany]; rubella with Rubenostika [Organon Teknica, Boxtel, the Netherlands]). The vaccines compared were: A: E-Zagreb, L-Zagreb, and Wistar RA 27/3 (Tresivac); B: Moraten, J-Lynn, and Wistar RA 27/3 (M-M-R II); and C: Schwarz, Urabe AM-9, and Wistar RA 27/3 (Trimovax). RESULTS: Before vaccination, 79.2 percent [95 percent confidence interval (CI) = 76.0 percent-82.2 percent] of the samples were positive for measles, 69.4 percent (95 percent CI = 65.8 percent-72.8 percent) for mumps, and 55.4 percent (95 percent CI = 51.6 percent-59.2 percent) for rubella. After vaccination with the A, B, and C vaccines, seropositivity was 100.0 percent, 99.5 percent, and 100.0 percent, respectively for measles; 99.5 percent, 94.5 percent, and 92.0 percent for mumps; and 92.6 percent, 91.3 percent, and 88.6 percent for rubella. CONCLUSIONS: About one-fifth (20.8 percent) of the schoolchildren who could have been vaccinated against measles at age 9 months had levels of antibodies insufficient for protection. In the sample of schoolchildren without previous vaccination against mumps and rubella, high proportions of susceptible levels were found. All vaccines were immunogenic, but vaccine A yielded a seroconversion rate of 99.5 percent for the mumps component, which was significantly higher than the other two vaccines (P < 0.01).

OBJETIVO: Se evaluó la seroprevalencia para sarampión, paperas y rubéola en niños en edad escolar (6-12 años) antes y después de la administración de tres vacunas triples antivirales combinadas. MÉTODOS: Se colectaron 692 muestras de sangre antes de la vacunación y 636 muestras entre 21 y 30 días después de la vacunación a niños de dos escuelas municipales de Rio Grande do Sul, Brasil, durante 1996. Se investigó la seropositividad de anticuerpos de la clase IgG mediante un ensayo de inmunoadsorción enzimática tipo ELISA (sarampión y paperas con Enzygnost [Behring, Marburgo, Alemania] y rubéola con Rubenostika [Organon Teknica, Boxtel, Países Bajos]). Las vacunas comparadas fueron: a) E-Zagreb, L-Zagreb y Wistar RA 27/3 (Tresivac); b) Moraten, J-Lynn y Wistar RA 27/3 (M-M-R II); y c) Schwarz, Urabe AM-9 y Wistar RA 27/3 (Trimovax). RESULTADOS: Antes de la vacunación, 79,2 por ciento (intervalo de confianza [IC] 95 por ciento: 76,0 a 82,2) de las muestras fueron positivas para sarampión, 69,4 por ciento (IC 95 por ciento: 65,8 a 72,8) para paperas y 55,4 por ciento (IC 95 por ciento: 51,6 a 59,2) para rubéola. Después de la vacunación con las vacunas A, B y C, la seropositividad fue de 100 por ciento, 99,5 por ciento y 100 por ciento, respectivamente para sarampión; de 99,5 por ciento, 94,5 por ciento y 92,0 por ciento para paperas; y de 92,6 por ciento, 92,3 por ciento y 88,6 por ciento para rubéola. CONCLUSIONES: Alrededor de un quinto (20,8 por ciento) de los escolares que pudieron haber sido vacunados contra el sarampión a los 9 meses de edad tenían niveles de anticuerpos insuficientes para protegerlos. En la muestra de escolares sin vacunación previa contra paperas y rubéola se encontró una alta proporción de niños susceptibles. Todas las vacunas fueron inmunogénicas, pero la vacuna A produjo una tasa de seroconversión de 99,5 por ciento para el componente de paperas, significativamente mayor que la de las otras dos vacunas (P < 0,01).

An evaluation of the adverse reaction potential of three measles-mumps-rubella combination vaccines

Objective. To compare the incidence of adverse events following the administration of three commercially available measles-mumps-rubella (MMR) combination vaccines. Methods. A randomized double-blind clinical trial was performed in 1996 that involved a total of 10 142 students 6-12 years of age in the state of Rio Grande do Sul, in Brazil. An MMR vaccine containing the Edmonston-Zagreb, Leningrad-Zagreb, and RA 27/3 strains ("vaccine A") was administered to 2 226 students (21.9 percent of the total); an MMR vaccine with the Moraten, Jeryl Lynn, and Wistar 27/3 strains ("vaccine B") was administered to 2 216 children (21.8 percent); and an MMR vaccine containing the Schwartz, Urabe AM-9, and Wistar 27/3 strains ("vaccine C") was given to 2 179 students (21.5 percent). A control group of 3 521 students (34.7 percent) was not vaccinated. Both the vaccinated subjects and the control subjects were followed daily for 30 days to detect any clinical manifestations. Results. Adverse events were more frequent in the vaccinated children than in the control group (P < 0.01). In terms of causing parotitis, vaccine A had a relative risk (RR) of 5.72 (95 percent confidence interval (CI) = 3.11-10.54) when compared with vaccine B, and an RR of 2.33 (95 percent CI = 1.52-3.58) when compared with vaccine C. Vaccine A was also associated with an increased risk of lymphadenopathy when compared with vaccine B (RR = 3.11; 95 percent CI = 1.78-5.45) and with vaccine C (RR = 2.22; 95 percent CI = 1.35-3.66). Vaccine C was associated with an increased risk of parotitis when compared with vaccine B (RR = 2.46; 95 percent CI = 1.26-4.80). Three cases of aseptic meningitis were detected among the children in the study group, but only one case of vaccine-related aseptic meningitis was identified, among the children receiving vaccine A. Conclusions. The three MMR vaccines that we studied are associated with different risks of adverse events. We found vaccine A to cause more reactions than the two other vaccines, especially vaccine B. In addition, vaccine A presented both a temporal and a cause-and-effect association with one case of aseptic meningitis. We hope that this study will contribute information that can be used in choosing MMR vaccines with safe and effective strains, especially for mass vaccination strategies