Study of the immune response engendered by differents combined measles, mumps and rubella (MMR) vaccines in an area of Andalusia (Spain)

Abstract

The objective of the study is to evaluate and compare the degree of serological protection conferred by the three components of two MMR vaccines: “Vac triple MSD ®” (Aventis Pasteur MSD) and “Triviraten ®” (Berna), and to study the effects of a second dose of “Priorix ®” (Glaxo SmithKline), in an unprotected population. In March 2001, this study was conducted in a sample of 86 children aged 3 and 4 years, in two Basic Health Zones of Cádiz (Spain). Mumps, measles and rubella antibody titers were evaluated by IgG enzyme linked immunosorbent assay (ELISA). All the children showing lack of response were revaccinated with the vaccine “Priorix ®” of GSK; in 12 of these children (all vaccinated previously with “Triviraten ®”), studies confirmed the existence of seroconversion utilizing the same methodology. The most outstanding finding has been the low percentage of children vaccinated with “Triviraten ®” possessing protective titers (>1:500) against mumps (14.3%) compared with those vaccinated with “Vac triple MSD ®” (81.1%, P<0.000001); geometric mean values (GMT) of 164 and 1631, respectively, were obtained. Significant differences, and in the same direction, were also found in respect of measles (83.7 and 100%, and GMT of 889 and 5076), although not so striking. However, all the children studied did have protective titres (>16 UI/ml) of antibodies against rubella. Of the 12 children studied who had not responded with protective titers of anti-mumps antibodies, eight children (66.7%) showed seroconversion with “Priorix ®”, and only one child (25%) presented seroconversion in the response to measles. We have thus proved that the “Rubini” strain provides insufficient protection against mumps in our child population. We have also found that the “Edmonston–Zagreb” strain confers less protection against measles than the “Enders” strain, although the “Schwarz” strain, after revaccination of the children who had failed with the “Edmonston–Zagreb” strain, did not achieve a satisfactory seroconversion, either.