Immunogenicity of standard dose Edmonston-Zagreb measles vaccine in highland Papua New Guinean children from four months of age.

A small-scale trial was carried out at Tari in the Southern Highlands Province of Papua New Guinea to determine the effectiveness of a standard subcutaneous dose of Edmonston-Zagreb measles vaccine (Institute of Immunology, Zagreb) administered to children at less than 8 months of age. Specific antibody levels were measured before and 7-11 weeks after vaccination using an ELISA system. Paired sera from 41 children vaccinated at 4-7 months of age and from 18 children vaccinated routinely at 8-29 months of age were available for comparison. No child 6 months of age or older had detectable maternal antibodies and all of these seroconverted. Post-vaccination titres in 12 children aged 6-7 months were not significantly different from those in older children and 1 year later, post-vaccination titres were still high. In Papua New Guinea, and perhaps in other developing countries, it may prove appropriate and acceptable to vaccinate with Edmonston-Zagreb measles vaccine at 6 months of age without recourse to augmentation of dose from that currently recommended in older children.