A collaborative study of cytomegalovirus antibodies in mothers and young children in 19 countries.

Regional variations in the incidence of cytomegalovirus (CMV) injections in mothers and young children were investigated by testing cord blood and serum samples from infants and children up to four years old for the presence of CMV antibodies in 19 different regions of the world. The samples were tested by both the local virus laboratory and the reference laboratory, using the same batch of complement-fixing CMV antigen and techniques which were validated by comparison of the titres recorded for samples of coded sera sent to each laboratory. The incidence of CMV antibodies varied from 44-100% in mothers and from 3-95% in young children. The number of children with CMV antibodies increased with age in five areas; suggesting that there was some child to child transmission of CMV infection between children in these regions. In the other regions, the absence of any significant age-related increase indicated that the main pathway of CMV infection in early life was by transmission from mothers to their infants. The significance of these findings is discussed.