Incidence of haemagglutinating antibodies to meningococci in north-west England.

USING AN INDIRECT HAEMAGGLUTINATION TECHNIQUE THE INCIDENCE OF MENINGOCOCCAL ANTIBODIES IN ADULTS WAS FOUND TO BE: group A 21%, group B 3%, and group C 20%. The reasons for some differences between these results and those obtained in America are discussed. A low incidence of antibody was detected in preschool children but the incidence in school children was found to approach that of adults. Comparison of the antibody incidence in the adult population of an area where clinical infections were occurring with that in a similar population elsewhere failed to detect any significant difference.