EFFECT OF HAEMOPHILUS-INFLUENZAE TYPE-B CONJUGATE VACCINE IN COMBINATION WITH PERORAL IMMUNIZATION WITH ESCHERICHIA-COLI ON EXPERIMENTAL OTITIS-MEDIA

The protective ability of a conjugated Haemophilus influenzae type b v accine, ACT-HIB(R), used singly or in combination with orally administ ered Escherichia coli, was investigated in a rat model for acute otiti s media. The humoral response to ACT-HIB(R) was also analyzed. The stu dy demonstrated that ACT-HIB(R) vaccination resulted in a prompt antib ody response, and that ACT-HIB(R) was efficient in preventing middle e ar infections caused by Haemophilus influenzae type b. The efficiency increased if the vaccine was combined with Escherichia coli. The resul ts suggest that Escherichia coli could possibly be useful in the futur e as a vaccine vehicle, and since Haemophilus influenzae acute mastoid itis seems to be almost exclusively due to serotype b, the incidence o f this infection may be reduced with the conjugated Haemophilus influe nzae type b vaccines.