Inmunización en gran escala contra el sarampión en Chile / Mass measles immunization in Chile

ABSTRACT

The results obtained in Chile after three years of vaccination with the Edmonston B strain of Enders attenuated vaccine have been reported. More than 620,000 children from eight months to five years of age - 54.7 per cent of the population in that age range - have been vaccinated. The serological studies reveal the persistence of serum antibodies for at least three years; good immunological response in underfed children; unsatisfactory serological response in infants under nine months of age. The total number of deaths in 1965 was the lowest registered in the last five years, and was 2,053 lower than in 1964. An epidemic occurred in the Province of Magallanes at the same time that vaccination was being carried out; this permitted demonstration of the high level of efficacy of the vaccine, through a comparison of the measles rates among vaccinated and among unvaccinated children. A 30-month follow-up of about 2,000 vaccinated and 2,000 unvaccinated children showed 12 cases of measles with one death in the vaccinated group, as against 340 cases with 24 deaths in the control group. An investigation of children hospitalized in Santiago was carried out during 1965. At that time 43 per cent of the city's population between eight months and five years of age had been vaccinated; 256 unvaccinated children were hospitalized with measles and there were 30 deaths, whereas only 5 vaccinated children