[Investigations on the immune response against meningococcal polysaccharide in children (author's transl)].

Children between the 2nd and 5th, respectively between the 7th and 10th year were immunized with meningococcal vaccine A + C in comparison to adults. The vaccines contained 50 micrograms of meningococcal polysaccharide A and C and fulfilled the requirements of the WHO. Antibodies were determined before and 4 weeks after vaccination by means of the bactericidal microassay. All age groups showed a distinct immune response to polysaccharide A and polysaccharide C. The mean titer increase was between 4.5 and 9.3 titer steps, the conversion rate ranged from 71% to 100%. In the youngest age group a positive correlation between age and mean titer increase was found in prevaccinal seronegative children as well as in prevaccinal seropositve ones. In all age classes prevaccinal seronegative children showed a significant higher titer increase than prevaccinal seropositive ones. A negative correlation was found between prevaccinal titers and titer increase in all age groups with polysaccharide A and polysaccharide C.