ABSTRACT
Background: Results of clinical and epidemiological studies confirm that no cases of measles have occurred in Chile since 1993. However, since covering of vaccination programs do not exceed 95 percent, an immunological surveillance for this disease is warranted. Aim: To know the immune status against measles and rubella in the Chilean population. Material and methods: A serological census of a representative sample of communities with high (90 percent or more) or low immunization coverings was performed. Four sub samples along the country were selected: 122 children aged 18 months of age (stratum A), 1,276 children attending the first year of basic school (stratum B), 899 teenagers in their last high school year (stratum C) and 399 women attending a family planning clinic (stratum D). IgG antibodies against measles and rubella were measured using ELISA and hemagglutination inhibition techniques, respectively. Results: Antibodies against measles and rubella were found in 96 percent and 94 percent of study subjects. No differences in these titres were found between different strata or communities with high or low vaccination covering. There is a high percentage of positive antibodies against measles among children of 18 months of age and a high percentage of antibodies against rubella among teenagers and women in family planning. Only 3 percent of the sample had not received any vaccine at the moment of the study. Conclusions: The high prevalence of antibodies against rubella allows to conclude that it is not necessary to consider this antigen in the next vaccination campaign. Due to the high prevalence of antibodies against measles, only the population older than 20 years old should be affected by the disease if this virus enters the country
Subject(s)
Humans , Male , Female , Infant , Child, Preschool , Adolescent , Adult , Antibodies, Viral/immunology , Rubella/immunology , Measles/immunology , Chile/epidemiology , Simple Random Sampling , Age Distribution , Seroepidemiologic Studies , Antibody Formation , Immunization Programs/statistics & numerical data , Rubella/prevention & control , Measles/prevention & control , Rubella Vaccine/immunologySubject(s)
Humans , Infant, Newborn , Tuberculosis/prevention & control , BCG Vaccine/administration & dosage , Tuberculosis/diagnosis , Tuberculosis/immunology , Tuberculin Test , BCG Vaccine/pharmacology , Treatment Outcome , Hypersensitivity, Delayed/chemically induced , Antibody Formation , Immunization, Secondary , Double-Blind MethodABSTRACT
Hasta la década de los 60, el sarampión era una importante causa de morbimortalidad en Chile. La vacunación programática, iniciada en 1963, tuvo un impacto real en disminuir tanto las tasas de morbilidad como las de mortalidad. Sin embargo, se produjo una epidemia entre los años 1988 y 1989 a pesar de una alta cobertura de vacunación; algunas razones para ello fueron la aplicación de la vacuna antes del año de edad y deficiencias documerytadas en la cadena de frío. Con posterioridad, un nuevo esquema de vacunación a los 12 meses de edad, la revacunación en edad escolar, mejorías en la cadena de frío, coberturas de vacunación superiores al 95 por ciento, y una campaña nacional de vacunación anti sarampión a menores de 15 años, durante 1992, permitieron cortar la transmisión del sarampión. Un programa especial de vigilancia, con estudio serológico de todos los casos sospechosos de sarampión, detectó un último paciente, infección adquirida en el exterior, en Enero de 1993. Durante 1996, se reforzó la inmunidad contra la enfermedad mediante una nueva campaña orientada a vacunar la población bajo 1 5 años de edad. Hoy en día, los adultos jóvenes constituyen la población susceptible, y en riesgo, de contraer el sarampión