The purpose of this study is to describe respiratory syncytial virus (RSV) hospitalization rates and to begin to address the utilization of outpatient resources for RSV medically-attended lower respiratory tract infections (MALRI) in 32-35 week gestational age (GA) premature infants who are less than 6 months of age and do not receive treatment.

The goals of this study are:

• To estimate the incidence of hospitalization attributable to RSV within 150 days from enrollment in premature infants who are:

  • 32-35 weeks GA
  • less than 6 months of age at the start of the RSV season
  • not receiving palivizumab prophylaxis and not recommended to receive palivizumab according to the AAP guidelines

• To estimate the incidence rate of hospitalization attributable to RSV in the other relevant study populations and time periods (e.g., Cohort 2, Cohorts 1 and 2 combined, and subgroups based on chronological age at the start of the RSV season, GA, etc. within 150 days from enrollment and other time periods based on RSV activity, etc.)

• To estimate the incidence of RSV-associated MALRI in the study populations

• To characterize the incidence and type of clinical interventions for MALRI in the study populations

Inclusion Criteria:

• Parent/legal guardian able to understand and provide written informed consent

• Male or female infants born at 32-35 weeks GA. GA will be determined according to available medical records.

• Clinically stable, in the opinion of the investigator

• Ability and willingness of the subject's parent/legal guardian to complete all protocol mandated follow-up telephone calls, visits and procedures

• Not more than one of the following American Academy of Pediatrics (AAP)-defined risk factors:

  1. Childcare attendance
  2. School-aged siblings in the home
  3. Exposure to environmental air pollutants (not including passive exposure to tobacco smoke)
  4. Congenital abnormalities of the airways
  5. Severe neuromuscular disease, as determined by the investigator

• Subject must meet the criteria listed below for either Cohort 1 or Cohort 2:

Cohort 1

• Date of enrollment between 01/Oct and 15/Dec
• Chronological age of < 6 months (i.e., has not yet reached 6-month birthday) at the traditional start of the local RSV season (as used to determine eligibility for RSV prophylaxis)

Cohort 2

• Date of enrollment between 16/Dec and 15/Feb
• Born during the current RSV season and discharged from the hospital nursery after 01/Dec

Exclusion Criteria:

• Previous (within 90 days of enrollment) or concurrent treatment with palivizumab or RSV-IGIV or IVIG
• Hospitalization at the time of enrollment (unless discharge is anticipated within 10 days)
• Two or more AAP-defined risk factors as listed under Inclusion Criteria
• Participation in trials of investigational RSV prophylaxis or therapeutic agents
• Confirmed prior or current RSV infection (a child with current signs/symptoms of respiratory infection must have negative RSV testing)
• Diagnosis of chronic lung disease (CLD) of prematurity (formerly referred to as bronchopulmonary dysplasia [BPD])
• Diagnosis of hemodynamically significant congenital heart disease (CHD), defined as requiring medication or supplemental oxygen for their CHD
• Known immunodeficiency
• Life expectancy of < 6 months

2 cohorts of premature infants and premature newborns 32-35 weeks