SUSCEPTIBILITY TO RUBELLA INFECTION IN FEMALES AT HIGH-RISK - IMMUNE PROTECTION ASSOCIATED TO POPULATION-DENSITY

Susceptibility to rubella in 428 Mexican females of childbearing age f rom four sanitary areas confined to a Mexican State (Queretaro) was de termined, Members of the group were residents of urban and rural commu nities and selected by random sampling. Anti-viral antibodies were det ermined by inhibition of haemagglutination. Concentration was expresse d as International Units of IgG anti-rubella haemagglutinin (IU/ml), A ntibody concentrations lower than 15.6 (IU/ml) were regarded as non-pr otective. The percentage of women immune-protected to rubella in the a reas varied from 28.8 to 75.6 with an average of 61.9. The difference in percentages of immune-protected females within the areas was statis tically significant (chi(2) = 48.26 and p<0.001). Immune protection wa s associated to population density, with less protection in less popul ated areas, Our results differ from the reported values of a serosurve y performed in the same state one year before: immune protection 61.9% versus 79.96%, respectively.