Rubella in Umbria (Italy): serological assessment of immunity in adult women and congenital rubella detection after 1978.

Antibody to rubella virus was measured in 3655 serum samples collected during 1973-1979 from females of child bearing age in Umbria (Italy). The overall incidence of seronegatives was 24 percent (hemagglutination inhibition (HAI) antibody less than 1:16), with a higher proportion of seronegatives in the first years studied (1973-1976). A history of rubella infection was shown to be an unreliable index of immunity. One case of rubella congenital syndrome was detected following laboratory screening of newborn babies after the rubella virus circulation in Umbria during 1978. The persistence of a risk associated with rubella virus in women living in Umbria indicates the importance and the urgency of the adoption of a full-scale rubella control campaign.