To establish the antibody response rate in children with recurrent infections and fully immunized with the Pneumococcal 7-valent Conjugate vaccine.

We have analyzed 39 patients referred to our clinic with recurrent infections despite complete immunization with the Pneumococcal 7-valent Conjugate vaccine for age, according to ACIP guidelines. We assessed the patients by checking their immunization status and the antibody titers to all 7 Streptococcus pneumoniae serotypes included in the vaccine (4, 6B, 9V, 14, 18C, 19F, 23F) assessed by standardized ELISA. The patients were assembled into 3 groups, a non-immunized group with laboratory data prior to the vaccine, and an immunized group consisting of responders and non-responders according to their antibody titer (>1.3 or <1.3 IU/ml respectively). The data were analyzed using Epi Info and SPSS.

The mean age was 3.8 years for responders and 3.3 years for non-responders. There was no significant statistical difference between the groups regarding age, race and sex. Ten patients were identified who failed to respond to all 7 serotypes included in the Pneumococcal 7-valent Conjugate vaccine. There was no significant statistical difference between the non-immunized and the immunized non-responders to all 7 serotypes.

We have identified a special immunological phenotype of specific antibody deficiency (SAD) patients with normal total immunoglobulins and normal responses to protein antigens, but who failed to respond to conjugate pneumococcal polysaccharides.