1766. Risk Factors for Outpatient Illness due to Respiratory Viruses in US Preterm Infants: Findings from a Two-Year Prospective Cohort Study
Session: Poster Abstract Session: Viral Infections; Pathogenesis and Epidemiology
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Background: Preterm infants are at high risk for severe RSV disease. Risk factors for various respiratory viruses in preterm infants are not well established.

Methods: In the RSV Respiratory Events Among Preterm Infants Outcomes and Risk Tracking (REPORT) study, preterm infants <6 months of age born between 32-35 weeks GA not receiving RSV prophylaxis were prospectively enrolled from 188 US clinics and followed during September–May of 2009–2010 or 2010–2011. Nasal and throat swabs were collected during outpatient medically-attended acute respiratory illnesses (MAARI). Samples were tested for RSV, influenza A and B, adenovirus, human metapneumovirus (hMPV), and parainfluenza virus types (PIV) 1-3 using quantitative reverse transcriptase PCR (qRT-PCR). Epidemiological risk factors were collected and evaluated separately for each virus using a multivariate Cox proportional hazard model with calendar time input; the model was fit iteratively until all remaining risk factors were statistically significant (P<0.05).

Results: 1646 subjects were enrolled. RSV was detected in 259 subjects, adenovirus in 149, PIV3 in 129, hMPV in 77, influenza A in 30, influenza B in 19, PIV1 in 15. Crowded living conditions (>5 people in home) or preschool-aged siblings increased the risks of MAARI due to RSV, adenovirus, influenza B, PIV1, and hMPV. Older subject age (>6 mos vs ≤6 mos) and daycare attendance increased the risks of MAARI due to RSV, adenovirus, and PIV3. Adenovirus risk was associated with family history of asthma and multiple births. Influenza A risk was associated with prior lower respiratory tract illness and tobacco smoke exposure. Current breastfeeding reduced the risks of MAARI due to adenovirus and influenza B.

Conclusion: Among preterm infants 32-35 weeks GA not receiving RSV prophylaxis, RSV was the principal cause of MAARI between September and May. Risk factors for disease vary by pathogen and inform efforts to reduce MAARI among high-risk preterm infants.

Eric A. F. Simoes, MB BS, DCH, MD1, Evan J. Anderson, MD2, Christopher S. Ambrose, MD3, Xionghua Wu, PhD3 and Jessie R. Groothuis, MD4, (1)University of Colorado School of Medicine, Aurora, CO, (2)Pediatrics and Medicine, Emory University School of Medicine, Atlanta, GA, (3)MedImmune, LLC, Gaithersburg, MD, (4)Former Employee of MedImmune, LLC, Santa Fe, NM


E. A. F. Simoes, MedImmune, LLC: Grant Investigator, Research grant

E. J. Anderson, None

C. S. Ambrose, MedImmune, LLC: Employee, Salary

X. Wu, MedImmune, LLC: Employee, Salary

J. R. Groothuis, MedImmune, LLC: Consultant and Employee, Consulting fee and Salary

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