Abstract
BACKGROUND: Human parainfluenza viruses (PIV) are a leading cause of pediatric acute respiratory infection (ARI), yet limited data exist on PIV-associated hospitalizations, particularly from serotype PIV-4, a serotype reported to cause severe disease. We describe the characteristics and seasonality of PIV-associated ARI hospitalizations, focusing on PIV-4. METHODS: During 12/01/2016-03/31/2020, we enrolled children hospitalized with fever or respiratory symptoms at the 7 children’s hospitals of the CDC’s New Vaccine Surveillance Network. Molecular testing for rhino/enterovirus (RV/EV), respiratory syncytial virus (RSV), influenza virus, PIV (serotypes 1-4), human metapneumovirus, and adenovirus were performed on mid-turbinate nasal or throat specimens collected from enrolled children. Parent interviews and chart abstractions were performed. RESULTS: A PIV was detected in 1,004 (6%) of 16,282 enrolled children. A PIV and another respiratory virus (most frequently with RV/EV or RSV) were detected in 336 (33%) children; 668 (67%) children tested positive for only 1 PIV (no co-detection of any other virus or co-detected PIV), including PIV-1 (33%), PIV-2 (15%), PIV-3 (40%), and PIV-4 (12%) (Table 1). Among children with only 1 PIV detected, children with PIV-4 infection were older (mean age 3.1 y) and more likely to have an underlying medical condition than children infected with other PIV serotypes. Discharge diagnoses of asthma, otitis media, and pneumonia were most common in children with PIV-4, and croup most common in those with PIV-1 & 2 (Table 2). PIV-1 had biennial fall seasonality; PIV-2 was detected mostly during the fall of 2018; PIV-3 detections peaked annually in the spring; and PIV-4 was detected year-round (Figure). One in 6 children required ICU care. [Figure: see text] [Figure: see text] [Figure: see text] CONCLUSION: PIV infections were detected in 6% of ARI hospitalizations and occurred throughout the year, with seasonal variation in serotype dominance. Half of children with PIV-related hospitalizations were healthy (without underlying medical conditions). Severe disease (requirement for ICU care) was common in all PIV-associated hospitalizations. Research on PIV vaccines is warranted, with consideration to include PIV-4. DISCLOSURES: John V. Williams, MD, Merck: Grant/Research Support|Quidel: Board Member Marian G. Michaels, MD, MPH, Merck: Grant/Research Support|Viracor: Grant/Research Support Janet A. Englund, MD, Ark Biopharma: Advisor/Consultant|AstraZeneca: Advisor/Consultant|AstraZeneca: Grant/Research Support|GlaxoSmithKline: Grant/Research Support|Meissa Vaccines: Advisor/Consultant|Merck: Grant/Research Support|Moderna: Advisor/Consultant|Moderna: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Sanofi Pasteur: Advisor/Consultant Mary A. Staat, MD, MPH, CDC: Grant/Research Support|Cepheid: Grant/Research Support|Merck: Grant/Research Support|NIH: Grant/Research Support|Pfizer: Grant/Research Support|Up-To-Date: Honoraria Elizabeth P. Schlaudecker, MD, MPH, Pfizer: Grant/Research Support|Sanofi Pasteur: Advisor/Consultant Rangaraj Selvarangan, BVSc, PhD, D(ABMM), FIDSA, FAAM, Abbott: Honoraria|Altona Diagnostics: Grant/Research Support|Baebies Inc: Advisor/Consultant|BioMerieux: Advisor/Consultant|BioMerieux: Grant/Research Support|Bio-Rad: Grant/Research Support|Cepheid: Grant/Research Support|GSK: Advisor/Consultant|Hologic: Grant/Research Support|Lab Simply: Advisor/Consultant|Luminex: Grant/Research Support Natasha B. Halasa, MD, MPH, Merck: Grant/Research Support|Quidell: Grant/Research Support|Quidell: donation of kits|Sanofi: Grant/Research Support|Sanofi: vaccine support Geoffrey A. Weinberg, MD, Merck & Co: Honoraria