Molecular Detection of Human Rhinovirus in Hospitalized Kansas City Children (2009-2012): Demographics, Chest Radiograph Findings and Length of Stay in Relation to Pre-existing Comorbidity.

Background: Human rhinovirus (HRV) is the pediatric respiratory virus most often detected by routine molecular diagnostics. The relevance/utility of HRV detection remains unclear. We performed a 40-month retrospective review of hospitalized children (Jan 2009-May 2012).

Methods: Multiplex PCR testing detected >1 virus in 2375 patients (1290 HRV/enterovirus (EV)). Excluding nosocomial HRV, confirmed EV, NICU/immunocompromised patients, and charts with missing data, 617 charts were reviewed. Chest X-rays (CXR) were interpreted by a blinded pediatric radiologist. Admission groups and definition: 1. Bacterial N= 72 (11.7%): confirmed serious bacterial infection (SBI); 2. Equivocal N=37 (5.6%): pneumonia unconfirmed as bacterial or viral; 3. Nonbacterial N=509 (82.6%). Pre-existing co-morbidities were noted in 154/617.Results: HRV was the sole virus in 85%. Peak HRV detection was Mar-May and Sept-Nov. Male/female ratio was 329/288; 76% were <3 yrs old. There were 55 PICU stays (15 bacterial and 35 nonbacterial). HRV results were available at Mn 1.54d (0-8.5) post admit but returned after hospital discharge (D/C) for 177/617.

For all 509 nonbacterial admits, the D/C rate by 48hr after HRV results were available was 46% and Mn length of stay (LOS) was 8.1d (range 0-402d, St Dev +27.3). For the N=439 with HRV results available to clinicians before patient D/C, the D/C rate was 57% and LOS 8.2d (0-196, +13.6). The D/C rates at both 24hr and 48hr after HRV-results became available were less, p<0.001, for patients with pre-existing co-morbidity (23.7% and 33%) vs for previously healthy patients (57.4% and 67% respectively). A co-morbidity effect on D/C rate and LOS held true for PICU admits (p=0.02). CXR on 386 patients (SBIs excluded) showed 74 normal, 2 atelectasis only, 211 viral pattern, 25 bacterial pattern, and 74 mixed pattern. CXR suggested underlying chronic lung disease in 39 and congenital heart disease in 31.

Conclusion: Almost 90% of non-SBI admits had HRV as the sole detected pathogen (70%of PICU cases). 3/4 of HRV occurred in children <3 years old. Molecularly detected HRV was associated with early D/C for previously healthy children. During admission, CXR patterns in almost 2/3 HRV patients were inconsistent with a bacterial process. HRV seems an important pathogen in hospitalized, even previously healthy, children. Our data may allow less antibiotic use and early discharge.