[Immunity coverage against measles, rubella and parotiditis viruses in a juvenile population in Leon, Spain].

BACKGROUND

The immunity coverage, seroprevalence of IgG antibodies against infection by measles, rubella and parotiditis viruses in a juvenile population (50,398 children) was studied.

METHODS

Systematic sampling was performed among children from 5-14 years of age who had undergone clinical analysis in the health care area of Leon. The hypothesis of sampling was the most unfavorable (p = q = 0.5) and the size of the sample of 600 children. Information was collected on vaccination state, previous history of disease and place of residence. The presence/absence of IgG antibodies was investigated by a commercial immunoenzymatic technique (EIA-Stat Measles, Mumps, Rubella, Whittaker Bioproducts, USA).

RESULTS

Sixty percent of the children studied had IgG antibodies against the three virus, 27% against two and 9% against only one with absence of antibodies against the three virus in 3%. The seroprotection observed was significantly higher (p < 0.05) for measles (87% +/- 3%) that for the other two diseases (rubella 80% +/- 3% and parotiditis 77% +/- 3%). In the group of children with previous history of measles and parotiditis a higher percentage of antibodies (p < 0.01) was observed than in the group with previous history of vaccination (measles: 94% versus 84%, parotiditis: 90% versus 75%). No difference was observed in the case of rubella.

CONCLUSIONS

Vaccination is still the principal conditioning factor of the state of immunity of the juvenile population in Leon in relation with the diseases studied (measles, rubella, parotiditis). The place of residence (rural or urban) did not condition different immunity coverage in the sample studied. The susceptibility of infection for some of these virus continues to be high: measles 13%, rubella 20% and parotiditis 23%).