[Vaccination against measles at 6 months of age]

Measles immunization with the Edmonston Zagreb stain was carried out in 71 six-month-old infants. Proportions of subjects with immunity were 91% among the 47 subjects retested before one year of age and 100% among the 28 subjects retested between two and three years of age. These results support the WHO recommendation that measles immunization should be given at the age of six months. The concerns expressed by some about possible adverse effects of early measles immunization (decreased immune defenses) are discussed, as well as the transfer of maternal antibodies and persistence of these antibodies in the child. The obstacles to such studies in developing countries, including the need for repeated phlebotomies with centrifugation of specimens and freezing of sera, could be circumvented by the use of filter paper dried blood spot samples which seem to provide reliable results although with values somewhat lower than those found in frozen sera.