To determine the immune response of premature infants to meningococcal serogroup C capsular polysaccharide (MCC) and combined diphtheria-tetanus toxoids-acellular pertussis-Haemophilus influenzae type b (DTaP-Hib) conjugate vaccines, 105 infants born at <32 weeks' gestation had Hib IgG geometric mean concentrations (GMCs) and MCC serum bactericidal antibody (SBA) geometric mean titers (GMTs) measured 1 month after the third immunization. Term infants served as control subjects. Premature infants had Hib GMCs of 0.27 microg/mL, with 21% achieving GMCs>1.0 microg/mL, compared with 0.81 microg/mL and 46% in term infants (P<.001 and P=.003, respectively). The MCC SBA GMT was 398, with 99% achieving an SBA > or =8, compared with 380 and 98% in term infants (P=.84 and P=1.0, respectively). Hib IgG was associated with age at third immunization (P<.001). When combined with the DTaP vaccine used in this study, the Hib GMC of premature infants was extremely low. The SBA GMT to MCC was similar to that of term infants.

Four premature infants developed apnoeas severe enough to warrant resuscitation after immunisation with diphtheria, pertussis, and tetanus (DPT), and Haemophilus influenzae B (Hib). One required re-intubation and ventilation.Although apnoeas after immunisation are recognised, they are not well documented. It is time for further research to elucidate the best time to immunise such infants. (Arch Dis Child Fetal Neonatal Ed 1999;81:F67-F68) Keywords: immunisations; apnoeas; prematurity Case reportsFour previously stable premature infants, born under 30 weeks of gestation, developed profound apnoeic and bradycardic episodes within 24 hours of being immunised with diphtheria/tetanus/pertussis and Haemophilus influenzae B vaccines.Case 1 was a boy born at 29 weeks of gestation, weighing 1070 g, and ventilated for three days. His cerebral ultrasound scans were normal and his course unremarkable. He had no apnoeas and bradycardias for 13 days before immunisation. He received his first course of DTP and Hib at a corrected age of 36+4 weeks. Within a few hours of immunisation he had multiple profound apnoeas and bradycardias and required intubation and ventilation. He quickly improved and was extubated after 36 hours. A full septic screen including a nasopharyngeal aspirate for respiratory syncytial virus was negative. He underwent his second and third course at term and 6 weeks without event.Case 2 was a girl born at 26 weeks of gestation, weighing 740 g, and ventilated for 20 days. She sustained a pulmonary haemorrhage and required ligation of a patent ductus arteriosus (PDA). Her cerebral ultrasound scans were normal. Before vaccination she had only the occasional apnoea and bradycardia that required stimulation. At a corrected gestational age of 40 weeks she was immunised with her first course of DTP and Hib. Within 24 hours she was having multiple profound apnoeic episodes requiring resuscitation with bag and mask ventilation. These settled over the following day. The second and third courses were given a year later without any adverse eVects.Case 3 was a boy born at 26 weeks of gestation, weighing 750 g, and ventilated for 30 days. A PDA was closed with indomethacin. His cerebral ultrasound scans were normal. Apnoeas and bradycardias of prematurity had stopped 11 days before immunisation. At a corrected gestational age of 39 weeks he was immunised with his first course of DTP and Hib. Within 48 hours he went oV his feeds, became tachypnoiec, and sustained several apnoeic episodes with recorded drops in O 2 saturations. These required treatment with facial O 2 and suction, but settled over 24 hours. His second and third immunisations given a month apart were uneventful.Case 4 was a boy born at 27+6 weeks of gestational age, and weighing 900 g. He was ventilated for 5 weeks, developing recurrent pneumothoraces. A PDA was closed with indomethacin. He developed intraventricular haemorrhages and haemorrhagic hydrocephalus requiring a ventriculo-peritoneal shunt insertion. In the weeks leading up to immunisati...

Objective: To describe the immune response of preterm infants to a diphtheria/tetanus/three component acellular pertussis (DTaP) vaccine, under an accelerated schedule, and the effects of steroids on this response. To compare responses with those of term infants.

Aims: To describe the immune response of preterm infants to combined diphtheria/tetanus/5 component acellular pertussis-Haemophilus influenzae type b inactivated polio vaccine (DT5aP-Hib-IPV) and meningococcal serogroup C conjugate vaccine (MCC) under accelerated schedule. To compare results with term infants immunised with DT5aP-Hib-IPV and with historical data from preterm infants immunised with a DT3 component aP-Hib vaccine. Methods: Prospective observational study in preterm infants born at ,32 weeks gestation with comparison to contemporary cohort of term infants. DT5aP-Hib-IPV and MCC vaccines were given at 2, 3, and 4 months. Results: Fifty preterm infants (mean gestational age 28.5 weeks) completed the study. After three doses of vaccines Hib polysaccharide IgG geometric mean concentration (GMC) was 1.21 mg/ml with 80% >0.15 mg/ml; MCC serum bactericidal assay geometric mean titre (GMT) was 1245 with 100% >8. All infants achieved protective titres to diphtheria, tetanus, and the three poliovirus types with >80% achieving protective rises in IgG against the five pertussis antigens. Conclusion: Preterm infants immunised with DT5aP-Hib-IPV and MCC vaccines show IgG responses to Hib and MCC greater than seen historically in both term and preterm infants with a DT3aP-Hib vaccine, and for pertussis antigens and poliovirus type 1 responses similar to that seen in term infants immunised with DT5aP-Hib-IPV. Responses to poliovirus types 2 and 3 are reduced, but all infants achieved protective titres.