Panorama atual do sarampo no mundo: Risco de surtos nos grandes eventos no Brasil / Current landscape of measles in the world: risk of outbreaks in major events in Brazil

O sarampo é considerado uma das doenças infecciosas mais contagiosas do mundo (1), capaz de atingir todos os grupos etários, com risco particular em menores de cinco e naqueles entre 15 e 29 anos de idade (2), sendo uma das principais causas de morte evitáveis por vacina entre crianças (3). Frente aos recentes surtos de sarampo ocorridos no mundo, estaria o Brasil, que desde 2000 conseguiu eliminar a circulação do sarampo e na atualidade vem lidando apenas com surtos de pequena monta de casos importados, sob risco de grandes surtos durante a Copa do Mundo de 2014 e as Olimpíadas de 2016? Através de análises dos últimos surtos ocorridos em todo o mundo e pesquisa da cobertura vacinal no Brasil, os autores respondem a estas questões.

Measles is considered one of the most contagious diseases in the world (1). It’s able to reach all of age groups with particular risk in under five and 15-29 years old (2). It’s one of the main causes for evitable deaths for vaccine between children (3). According to recents measles outbreaks occurred in the world, Brazil is included in it, since 2000 has eliminated measles circulation and actually has been dealing with outbreaks of little dimension of imported cases, at risk of large outbreak during the World Cup 2014 and The Olympics Games 2016? Through analysis of the latest outbreaks ocurred all over the world and research of vaccine coverage in Brazil, the authors will answer to these questions.

Evaluación de la seroprotección contra sarampión, rubéola y hepatitis B en niños menores de cinco años del Perú, 2011 / Evaluation of the seroprotection against measles, rubella and hepatitis B in children under 5 years of age in Peru, 2011

Objetivos. Estimar la prevalencia de anticuerpos contra sarampión, rubéola y hepatitis B en niños de 1 a 4 años del Perú. Materiales y métodos. Se realizó una encuesta nacional basada en la aplicación de un cuestionario y obtención de muestra de sangre capilar en papel de filtro para el estudio de anticuerpos contra sarampión, rubéola y hepatitis B en niños de 1 a 4 años. Se utilizó un muestreo probabilístico, estratificado y multietápico con inferencia a nivel nacional y siete ámbitos de estudio: Lima metropolitana, resto de costa urbana, costa rural, sierra urbana, sierra rural, selva urbana y selva rural. Las muestras de sangre capilar fueron procesadas siguiendo protocolos estandarizados para la determinación de anticuerpos mediante técnica de ELISA utilizando reactivos comerciales. Resultados. Se encontró una prevalencia nacional de 91,6% (IC95%: 90,6-92,7%), 91,3% (IC 95%: 90,3-92,4%) y 95,9% (IC 95%: 95,0-96,8%) para anticuerpos contra sarampión, rubéola y hepatitis B respectivamente. No se evidenció diferencias significativas de las prevalencias entre los diferentes ámbitos de estudio y en los diferentes estratos socioeconómicos de los conglomerados. Conclusiones. En niños de 1 a 4 años se ha estimado una prevalencia nacional de anticuerpos contra sarampión y rubéola entre 90-93%, mientras que para anticuerpos contra hepatitis B (anti-HBsAg) entre 95-97%.

Objectives. To estimate the prevalence of antibodies against measles, rubella and hepatitis B in children aged between 1 and 4 years in Peru. Materials and methods. A national survey was conducted based on a questionnaire and capillary blood sample taken on filter paper in order to study antibodies against measles, rubella and hepatitis B in children from 1 to 4 years of age. A stratified, multistage, probability sampling design was used to be representative at the national level and at level of seven ambits, including the Metropolitan Lima Area, the rest of the urban coast, the rural coast, the urban highlands, the rural highlands, the urban jungle and the rural jungle. The capillary blood samples were processed according to the standardized protocols for detection of antibodies using the ELISA technique and commercial reagents. Results. The survey showed a national prevalence of antibodies against measles, rubella and hepatitis B of 91.6% (CI 95%: 90.6%; 92.7%), 91.3% (CI 95%: 90.3%; 92.4%) and 95.9% (CI 95%: 95.0%; 96.8%) respectively. There was no evidence of significant differences in the prevalence among the ambits of study or among the socioeconomic strata of the conglomerates for any of the three types of antibodies. Conclusions. In children from 1 to 4 years of age, the national prevalence of antibodies against measles and Rubella was between 90-93%, while the prevalence of antibodies against Hepatitis B (anti-HBsAg) was between 95-97%.

Investigation of measles IgM-seropositive cases of febrile rash illnesses in the absence of documented measles virus transmission, State of São Paulo, Brazil, 2000-2004 / Investigação dos casos de doenças febris exantemáticas com IgM reagente contra o sarampo na ausência de transmissão documentada do vírus do sarampo, Estado de São Paulo, 2000-2004

INTRODUCTION: To review measles IgM-positive cases of febrile rash illnesses in the State of São Paulo, Brazil, over the five-year period following interruption of measles virus transmission. METHODS: We reviewed 463 measles IgM-positive cases of febrile rash illness in the State of São Paulo, from 2000 to 2004. Individuals vaccinated against measles < 56 days prior to specimen collection were considered to be exposed to the vaccine. Serum from the acute and convalescent phases was tested for evidence of measles, rubella, parvovirus B19 and human herpes virus-6 infection. In the absence of seroconversion to measles immunoglobulin-G, measles IgM-positive cases were considered false positives in individuals with evidence of other viral infections. RESULTS: Among the 463 individuals with febrile rash illness who tested positive for measles IgM antibodies during the period, 297 (64 percent) were classified as exposed to the vaccine. Among the 166 cases that were not exposed to the vaccine, 109 (66 percent) were considered false positives based on the absence of seroconversion, among which 21 (13 percent) had evidence of rubella virus infection, 49 (30 percent) parvovirus B19 and 28 (17 percent) human herpes virus-6 infection. CONCLUSIONS: Following the interruption of measles virus transmission, thorough investigation of measles IgM-positive cases is required, especially among cases not exposed to the vaccine. Laboratory testing for etiologies of febrile rash illness aids interpretation of these cases.

INTRODUÇÃO: Revisar os casos de doenças febris exantemáticas com IgM reagente contra o sarampo, no Estado de São Paulo, Brasil, durante os cinco anos seguidos a interrupção da transmissão do vírus do sarampo. MÉTODOS: Nós revisamos 463 casos de doenças febris exantemáticas com IgM reagente contra o sarampo, no Estado de São Paulo, Brasil, de 2000 a 2004. Indivíduos vacinados contra o sarampo 56 dias antes da coleta de amostra foram considerados expostos à vacina. Soros da fase aguda e de convalescença foram testados para a evidência de infecção de sarampo, rubéola, parvovírus B19 e herpes vírus 6. Na ausência de soroconversão para imunoglobulina G contra o sarampo, casos com IgM reagente contra o sarampo foram considerados falsos positivos em pessoas com evidência de outras infecções virais. RESULTADOS: Entre as 463 pessoas com doenças febris exantemáticas que testaram positivo para anticorpos IgM contra o sarampo durante o período, 297 (64 por cento) pessoas foram classificadas como expostas à vacina. Entre os 166 casos não expostos à vacina, 109 (66 por cento) foram considerados falsos positivos baseado na ausência de soroconversão, dos quais 21 (13 por cento) tiveram evidência de infecção por vírus da rubéola, 49 (30 por cento) parvovírus B19 e 28 (17 por cento) infecção por herpes vírus humano 6. CONCLUSÕES: Após a interrupção da transmissão do vírus do sarampo é necessária exaustiva investigação dos casos com IgM reagente contra o sarampo, especialmente dos casos não expostos à vacina. Testes laboratoriais para etiologias das doenças febris exantemáticas ajudam na interpretação destes casos.

Could the MMR vaccine replace the measles vaccine at one year of age in Egypt?

This cross-sectional study evaluated the immune status of non-vaccinated healthy infants to determine if it is possible to replace both measles vaccine [at 9 months] and measles, mumps and rubella [MMR] vaccine [at 18 months] with a single dose of MMR at 12 months. Serum samples from 566 children in Alexandria, Egypt showed a significant decrease in the seropositive rate to the 3 viral diseases with increasing age, but a significant increase in the seropositive rate among infants who were ranked 1st or 2nd in their family, full-term or born to mothers with no history of hypertension during pregnancy. We recommend administration of the first dose of MMR vaccine between 9 and 12 months of age, and a booster dose of MMR vaccine at 4 years of age

Sarampión, Rubéola y SRC: Rubella Watch: Compendio de artículos sobre sarampión(1) / Measles, Rubella and SRC: Rubella Watch: Articles compendium on measles (1)

La publicación busca documentar la experiencia regional, pero sobretodo comunicar a los países y a otras regiones del mundo las lecciones aprendidas, así como las experiencias y mejores prácticas derivadas de la iniciativa de eliminación de enfermedades prevenibles por vacunación. Durante los 15 años de este proceso se ha acumulado conocimiento sobre lo que debe hacerse para llevar adelante estas iniciativas y lograr la meta de eliminación.

Avaliação vacinal e imunológica para sarampo no paciente pediátrico portador de insuficiência renal crônica / Vaccinal an immunological measles evaluation in pediatric patients with chronic renal failure

Objetivo: avaliar a imunidade para o sarampo em crianças e adolescentes portadores de insuficiência renal crônica. Casuística e métodos: no ano 2000, foi realizado um estudo de corte transversal com os pacientes seguidos em uma unidade de nefrologia que preenchessem os critérios seletivos: idade 18 meses e 18 anos, ritmo de filtração glomerular abaixo de 70 ml/min/1,73m2, que tivessem o cartão vacinal preconizado pelo Ministério da Saúde do Brasil...

Objective: to evaluate the immune response to measles vaccination in children and adolescents with chronic renal failure (CRF). Patients and methods: a cross-sectional study was proceeded in year 2000, with registered patients in a nephrologic unit, that fulfilled the study criteria: age range between 18 months and 18 years, glomerular filtration rate...

Measles and rubella antibody status in children after treatment for acute lymphoblastic leukemia

OBJETIVO: Avaliar a história vacinal e a situação da proteção vacinal contra sarampo e rubéola em crianças portadoras de leucemia linfóide aguda após o término do tratamento. MÉTODOS: O estado imunológico contra o sarampo e a rubéola foi avaliado pela técnica ELISA em 22 crianças com leucemia linfóide aguda após o término do tratamento. RESULTADOS: Dos 22 pacientes, 20 haviam recebido previamente duas doses da vacina do sarampo, e 18 deles, uma dose da vacina da rubéola. Soropositivos para sarampo e rubéola resultaram em 65 e 88,9 por cento, respectivamente, sem correlação com idade do paciente, agressividade do tratamento ou tempo decorrido entre final do tratamento e coleta da amostra. CONCLUSÃO: Detectamos falha na proteção vacinal contra sarampo e rubéola em 35 e 11,1 por cento dos casos, respectivamente. Recomendamos, ao final do tratamento para leucemia linfóide aguda, aplicar reforço da vacina contra sarampo, avaliar o estado imunológico contra rubéola e, se necessário, revacinar o paciente.

OBJECTIVE: To assess the vaccination history and the status of vaccine-induced protection from measles and rubella in children after treatment for acute lymphoblastic leukemia. METHODS: Measles and rubella immunological status was assessed by the ELISA technique for 22 children previously treated for acute lymphoblastic leukemia. RESULTS: From the total of 22 patients, 20 had been given two doses of measles vaccine and 18 had had one dose of rubella vaccine. The percentage of patients seropositive for measles and rubella were 65 and 88.9 percent, respectively, with no correlation with age of patient, aggression of treatment or the time passed between the end of treatment and sample collection. CONCLUSIONS: We detected that vaccination had failed against measles and rubella in 35 and 11.1 percent of cases, respectively. We recommend that a measles booster be given after the completion of treatment for acute lymphoblastic leukemia and that rubella immunity status should be assessed at this point, with revaccination performed when necessary.

Desarrollo de anticuerpos y frecuencia de eventos temporalmente asociados a las vacunas contra el sarampión y rubéola en personal de salud universitario de Jalisco / Antibody development and frequency of events temporarily with measles and rubella vaccines among university health personnel in Jalisco

Objetivo: Evaluar el estado inmune y la seroconversión o respuesta anamnésica posterior a inmunización con vacuna de sarampión-rubéola (SR) y eventos temporalmente asociados, en personal de salud universitario. Materiales y métodos: Estudio prospectivo, longitudinal y comparativo de mayo a junio de 2000 en 120 adultos sanos de un Hospital de la Universidad Autónoma de Guadalajara. Previo consentimiento informado se aplicó la vacuna SR de sarampión (Schwarz) y rubéola (RA 27/3). Se realizó seguimiento telefónico semanal para identificar eventos locales y sistémicos temporalmente asociados a la vacunación (30 días posteriores a su aplicación, no atribuibles a otro proceso mórbido). Se tomó suero antes y seis semanas después de la vacunación. Los anticuerpos (IgG) contra sarampión y rubéola fueron cuantificados por análisis inmunoenzimático (Enzygnost®, Dade Behring) con puntos de corte de > 300mUI/mL y > 8UI/mL, respectivamente. Análisis: media, desviación estándar (DS), Prueba t de Student pareada (significancia de P < 0.05). Resultados: Se logró seguimiento en 105/120 (87.5%) durante seis semanas. El 87.4% fue personal de salud y 44.6% varones. Rango de edad 17-71 años (mediana = 21). En la historia clínica hubo antecedente de posible sarampión en 57.1%. Se obtuvo suero pareado en 75 casos. La proporción de voluntarios con anticuerpos para sarampión y rubéola antes (90.7 y 94.7%) y después (100 y 100%) de la vacuna se incrementó de manera significativa (P < 0.001). Dolor, calor, rubor e induración en el sitio de inyección se presentó en 4/105 (~4%). Fiebre, exantema, artralgias y artritis en 9/105 (~9%). Conclusiones: La proporción de susceptibles a sarampión fue alta si tomamos en consideración la potencialidad de transmisión del virus de sarampión a la población que atenderían durante el período de contagiosidad (3-5 días). La respuesta de inmunidad postvacunal fue óptima. La vacunación en personal de salud debe ser prioritaria.

Objective: To evaluate the seroprevalence, seroconversion, anamnesic response and events temporally associated with immune status pre and post immunization with measles and rubella vaccine in health personnel from a public University in Guadalajara, Mexico. Material and methods: We carried out a prospective, longitudinal and comparative study from May to June 2000 among 120 healthy volunteers. Informed consent was obtained from all participants. We administered measles (Schwarz) and rubella (RA 27/3) vaccines. Weekly phone calls during six weeks were recorded from each volunteer to assess local and systemic events temporally associated with immunization non attributable to any other disease. Serum samples were obtained before and after vaccination in 75 volunteers. Antibodies against measles and rubella were measured by an enzyme immunoassay kit (Behring) with cut-off points of ³300mUI/mL and ³8UI/mL respectively. Statistical analysis included mean, standard deviation and paired Student's t-test (P < 0.05). Results: 105/120 participants (87.5%) were followed during 6 weeks. 87.4% were health personnel and 44.6% were males. The age range was 17-71 years (median = 21). We found a prior history of measles in 57.1%. Local events included pain, heat, redness and induration and were reported by 4/105. Systemic events such as fever, exanthema, pain in joints and arthritis was reported by 9/105. The proportion of study subjects with protective antibodies against measles and rubella prior to vaccination was 90.7 and 94.7% respectively. Both groups reached 100% after vaccination. Conclusions: The proportion of non-immune health personnel was low and similar to other reports. However, the potential spread of measles and rubella virus from a non-immunized infected health care provider could be amplified by the number of patients seen daily during the peak period of 3-5 days. The vaccination of health personnel should be encouraged.

Antibody response after measles immunization.

RATIONALE: Measles is still an important public health problem in Thailand despite measles vaccination being practiced since 1984. Vaccine failure is one of the suspected reasons for the high incidence of measles. OBJECTIVE: To study the seroconversion rate of 9-month-old infants and to study the antibody level in 18 month-old and 4 year-old children who had measles vaccination at 9 months of age. MATERIAL AND METHOD: Enrolled infants and children who attended the child health clinic for routine immunization at the Queen Sirikit National Institute of Child Health from March 1, 1994 to May 31, 1995. They were divided into 3 groups. Group A, 9 month-old infants who came for measles vaccination. Blood samples were drawn twice from these infants, before measles vaccination and 3 months later for measles antibody level. Group B and C were 18 month-old and 4-year-old children who came for their first and second DTP (Diphtheria, Tetanus, Pertussis vaccine) booster. One blood sample for measles antibody was drawn from the latter group of children. Measles antibody was determined by micro-neutralization technic at the National Institute of Health (NIH). The geometric mean antibody titer before and after measles vaccination was compared by using the paired t-test. RESULTS: There were 30, 31 and 34 infants/children in group A, B and C respectively. No significant measles antibody (NT antibody was less than 1:4) was detected in 93.5 per cent of 9-month-old infants. The seroconversion rate at 3 months after vaccination in group A children was 68.75 per cent while in group B, 9 months after vaccination it was 53.3 per cent. Ninety seven per cent of children in group C had NT antibody above 1:4. The geometric mean titer (GMT) of measles antibody in 9-month (before vaccination), 12-month, 18-month infants and 4 year old children was 1:2.5; 1:14.8, 1:8.2 and 1:73.8, respectively (p < 0.05). CONCLUSION: Almost 70 per cent of vaccinees at 9 months of age had seroconversion to measles vaccine with GMT of 1:14.8 while fifty three per cent of 18 month old children had an average GMT of 1:8.2. The GMT of the two groups was significantly different (p < 0.05). At 4 years of age almost all the children had NT antibody to measles with a GMT of 1:73.8 (p < 0.05) Vaccine failure is likely to be one factor responsible for the high incidence of measles after the introduction of measles vaccine into the Expanded Program of Immunization (EPI). The authors suggest giving a booster dose of measles at 15 months of age to boost the antibody level before waning of measles antibody at 18 months old, in order to protect this group of children from contracting measles.

Measles outbreak in a Periurban area of Chandigarh: need for improving vaccine coverage and strengthening surveillance.

OBJECTIVE: An outbreak of measles was investigated in the periurban areas of Chandigarh Union Territory, during the months of December 1998 to February 1999. Mainly the children below 15 years of age were affected. The children of migrant labourers belonging to the neighbouring states of Uttar Pradesh and Bihar constituted the majority of population in the area under study. They belonged to lower socio economic status with low immunization coverage. METHODS: A total of 2968 houses were surveyed for epidemiological investigations in the areas of colony No. 5, Ramdarbar, Palsora and Pandit colony of Kajheri, covering a population of 14,601 and 7.3% (216/2968) of families were affected in the outbreak. RESULTS: Two hundred and eighty three cases of measles were reported with an attack rate of 4.5% and male to female ratio of (M:F) 5.3%:3.6%. Among the measles cases, 48.8% had received measles vaccination. The outbreak was investigated by detecting measles specific IgG/IgM antibodies either in acute or convalescent serum samples or both. Due to inadequate surveillance system and containment measures, the outbreak was in full swing during the winter months. Measles related complications were reported in 31.1% cases (i.e. diarrhoea in 15.2% and Pneumonia is 7.1%). CONCLUSION: Following smallpox and guinea worm eradication, WHO's next thrust, is on eradication of poliomyelitis and measles. Hence, strengthening of disease surveillance as well as vaccination policies are mandatory to achieve disease control in these areas.

Measles antibody in the children in Ubon Ratchathani province.

Measles is a highly contagious disease, preventable by vaccine. Measles epidemics have been dramatically controlled since the introduction of live attenuated measles vaccine. Measles antibody is used as an indicator of previous natural infection or vaccination, and also as a marker of protective immunity. The authors determined measles IgG levels in 1,176 children in Ubon Ratchathani province by ELISA from September 1998 to January 1999. Two- hundred and sixty- five cases (22.5%) had antibodies below the protective level (< 320 mIU/ml). Antibodies were high during the neonatal period, then declined to below the protective level at 4-6 months of age, and were negative at age 7-11 months. An increase in antibody level after 1 year old might be the result of measles immunization at 9-12 months of age, then antibodies decreased to the lowest level at 3-5 years after immunization or 4-6 years of age. A second dose of immunization will increase the number of children who have antibodies above the protective level better than one dose of immunization and it is recommended to revaccinate at 4-6 years of age. There was no statistical difference of measles antibody between boys and girls in all age groups.

Post-vaccination scenario of measles: a retrospective analysis.

BACKGROUND: Routine vaccination against measles was introduced in India during 1985-86 through the Universal Immunization Programme. Its effect on the current prevalence of measles is not known. METHODS: Information on the total number of patients admitted and deaths due to measles from January 1982 to December 1997 were obtained from the records of the Institute of Tropical Medicine, Hyderabad, the only infectious diseases hospital in the city. Details on age, sex, number of complications, duration of hospital stay, vaccination status and information on vitamin A administration in the hospital were collected from the case records. RESULTS: A total of 20,926 cases of measles were admitted from 1982 to 1997. There was a 69% reduction in hospital admissions from the pre-vaccination to the post-vaccination period, and deaths due to measles decreased by 90%. Over the years, a rise in the age of children admitted with measles was observed. Boys were admitted more frequently to the hospital (p < 0.001) than girls. All the children showed one or more complications. From 1992 onwards, vitamin A was administered to 45.4% of the children admitted. CONCLUSION: A significant reduction was observed in the number of cases admitted to the hospital as well as deaths due to measles. Apart from the effect of the vaccination programme, this could also be due to increased awareness and availability of better health care facilities in the hospital and peripheral health clinics. Administration of vitamin A to children with measles as recommended by the World Health Organization needs to be implemented. A significant increase in the number of older children (> 5 years) with no significant reduction in the infants affected by measles indicates inadequate vaccine coverage and accumulation of susceptible older children.

Calibration and use of an in-house anti-measles IgG standard serum

For the purpose of research a large quantity of anti-measles IgG working reference serum was needed. A pool of sera from five teenagers was prepared and named Alexandre Herculano (AH). In order to calibrate the AH serum, 18 EIA assays were performed testing in parallel AH and the 2nd International Standard 1990, Anti-Measles Antibody, 66/202 (IS) in a range of dilutions (from 1/50 to 1/25600). A method which compared parallel lines resulting from the graphic representation of the results of laboratory tests was used to estimate the power of AH relative to IS. A computer programme written by one of the authors was used to analyze the data and make potency estimates. Another method of analysis was used, comparing logistic curves relating serum concentrations with optical density by EIA. For that purpose an existing computer programme (WRANL) was used. The potency of AH relative to IS, by either method, was estimated to be 2.4. As IS has 5000 milli international units (mIU) of anti-measles IgG per millilitre (ml), we concluded that AH has 12000 mIU/ml.

Soroconversäo da vacina tríplice viral em crianças de 9 e 15 meses de idade / Soroconversion of the MMR vaccine in childrens at 9 and 15 month

A resposta sorológica à vacina tríplice viral foi avaliada em 109 crianças de nove meses de idade, sem história prévia de vacinaçäo contra sarampo, e em 98 crianças de 15 meses de idade, que comprovadamente receberam a vacina monovalente contra o sarampo aos nove meses. A vacina trivalente utilizada continha as seguintes cepas de vírus do sarampo, cepa Urabe Am9 de vírus da caxumba e cepa Wistar RA 27/3 de vírus da rubéola. Um número significantemente maior de crianças do grupo de 15 meses de idade apresentava anticorpos pré-vacinais contra sarampo e caxumba. As taxas de soroconversäo para o sarampo, caxumba e rubéola foram elevadas em ambos os grupos, nä havendo diferenças estatisticamente significantes entre os mesmos. Os títulos de anticorpos pós-vacinais contra a rubéola foram significantemente mais elevados no grupo de crianças de 15 meses de idade. Nenhum evento adverso sério imputável à vacinaçäo foi ibservado.

Vigilancia de laboratorio en sarampión: Chile, 1992-1995 / Laboratory surveillance of measles: Chile, 1992-1995

Background: The first massive national measles vaccination campaign in Chile was done in 1992. Since then a laboratory surveillance of the disease has been undertaken at the Instituto de Salud Pública. Aim: To report the results of laboratory surveillance of measles between 1992 and 1995. Material and metbods: Paired serum samples from suspected cases of measles were received at the Institute. Measles specific IgG was determined with indirect immunofluorescence methods. IgG and IgM immunoenzymatic methods were used as complementary techiques, and rubella infections were ruled out by hemmaglutination inhibition tests. Results: Sera from 1087 presumptive cases (489 in 1992, 196 in 1993, 180 in 1994 and 222 in 1995) were analyzed. Only two cases of wild imported measles were confirmed, one in Arica in 1992 and the other in Santiago in 1993. Five additional post vaccine cases were detected. Eighty eight percent of samples in 1992 and 75 percent in 1994 were seropositive. A high percentage of cases were confirmed as rubella (55 percent in 1992 and 19 percent in 1994). Conclusions: Absence of wild measles virus circulation in Chile from 1992 to 1995 emphasizes the importance of laboratory surveillance of the disease

Evaluación de tres estrategias de vacunación contra el sarampión / Evaluation of three strategies of vaccination against measles

Objetivo: determinar la seroconversión a la vacuna del sarampión con las estrategias horizontal, casa a casa y jornada en las áreas norte y sur de la ciudad y comparar su efectividad. Metodología: prueba clínica, epidemiológica y serológica controlada en 776 niños entre 9 y 15 meses de edad, a quienes se les efectuó una determinación basal de anticuerpos (método de ELISA), luego se les administró la vacuna anti-sarampión y cuatro semanas después se les efectuó una segunda determinación de anticuerpos. Resultados: la más eficiente de las estrategias de vacunación fue la horizontal con una seroconversión del 94.3/100, luego casa a casa (89.7/100) y por último la de jornada (86.8/100). Conclusiones: El estudio comprobó que la estrategia horizontal o sea por demanda espontánea fue la mejor

Measles vaccine efficacy in India: a review.

Different workers have used different designs to assess effectiveness of live, further attenuated measles vaccine i.e., seroconversion studies, outbreak investigations, field trials and coverage survey methods. The results were often contradictory. We reanalyzed data from these studies to find out optimum vaccine efficacy (VE) and its determinants in the Indian context. Although nutritional status and sex of the subjects did not affect seroconversion rates, the rates were greater among initially seronegative and older children. Overall seroconversion rates in 9-11 months children ranged between 56 and 96%. Studies showing poor seroconversion had an inadequate sample size and/or technical flaws that detracted from the reliability of results. However, appropriately designed studies demonstrated seroconversion rates of more than 90% in 9-11 months children who were initially seronegative. Since 5-10% of 9-11 months old infants had persistent measles maternal antibody, measles vaccine may be around 85-90% effective in this age group. These results are in agreement with the findings observed in outbreak investigations. These outbreaks fulfilled all the criteria which are considered necessary for optimum estimation of VE in such settings; VE was found to be more than 90% in outbreak settings. Conversely, retrospective coverage surveys grossly under estimated VE (about 60%) which was probably due to misclassification of vaccination status of enrolled children. The surveys were undertaken in areas where immunization records were grossly incomplete and only few mothers retained immunization cards. Unfortunately, VE was also under estimated in field trials which were neither randomized nor blind, and no placebo injections were used in control children; many observations were on record which could explain the under estimation of VE. Reanalysis of data from different types of studies indicates that efficacy of measles vaccine given at 9-11 months of age is of the order of 85-90% in the Indian context.