The purpose of this study is to examine the relationship between receipt of DTaP and the occurrence of prolonged episodes of apnea and bradycardia in preterm infants, while employing a random control study design and an objective assessment of cardiorespiratory events.

The American Academy of Pediatrics (AAP) recommends the immunization of preterm infants at two months chronological age with the diphtheria-tetanus-acellular pertussis (DTaP) vaccine, regardless of birth weight and gestational age. However, several investigators, employing historical controls and subjective observations, have reported an increased incidence in prolonged apnea and bradycardia in preterm infants following immunization. Consequently, many primary care providers do not adhere to recommended AAP guidelines. The purpose of this study is to reexamine the relationship between receipt of DTaP and the occurrence of prolonged episodes of apnea and bradycardia in preterm infants, while employing a random control study design and an objective assessment of cardiorespiratory events.

Ten participating hospitals will enroll infants < 37 completed weeks gestational age into the study when they are 56-60 days chronological age. Infants are randomly assigned into one of two groups: One group receives DTaP immunization and the control group does not (until study is completed). Physiological event recording monitors are used continuously during the next 2 days to document the incidence of prolonged apnea (respiratory pause of ≥20 sec in duration or >15 sec in duration if associated with bradycardia for ≥5 sec) and prolonged bradycardia (heart rate <80 bpm that lasted ≥10 sec) in all infants. The presence and number of episodes during the 48-hour period will be compared between the 2 groups.

Inclusion Criteria:

• Born at a gestational age < 37 weeks.
• Still in the hospital at time of study.
• Between 56 - 60 days chronological age.

Exclusion Criteria:

• Had active infections, were critically ill, or had unstable vital signs.
• Requiring assisted ventilation or tracheostomy during the study.