1126. Novel H1N1 Influenza A Infection in Children: PCR Cycle threshold and Disease Severity
Session: Poster Abstract Session: Influenza and H1N1 Diagnosis, Epidemiology, and Viral Outcome
Saturday, October 22, 2011
Room: Poster Hall B1
Background:  The reasons why some hospitalized children with novel 2009 H1N1 influenza A infection had more severe disease compared to others are unclear. We hypothesize that children with severe and/or complicated disease have a higher respiratory viral burden than those with mild disease.

Methods:  We reviewed the medical records of children hospitalized at Children’s Hospital of Michigan with positive novel 2009 H1N1 Influenza A PCR from August 2009 through April 2010. Patients were divided based on their clinical presentations, complications and outcomes into 3 groups: group 1 included children with mild (M) disease; group 2 included children with moderate/progressive (M/P) disease and group 3 included children with severe/complicated (S/C) disease as defined by the CDC. We evaluated the respiratory viral load (RVL) using cycle threshold (CT) values of the influenza A PCR and assessed if these values correlate with disease severity.

Results:  103 children were included in our study. Their age range was 2 weeks to 18 years (mean 5.6, median 5). Males were more than females (2:1).  65 (63%) children had at least one coexisting comorbidity. Of all patients, 33 (32%) had M disease, 8 (8%) had M/P disease and 62 had S/C (60%) disease. Severe/complicated disease occurred in 38 (59%) of 65 patients with comorbidities compared to 24 (63%) of previously healthy children (p>0.05). The mean CT values were 27.01 (18.89-36.06) in group 1 (M), 27.00 (19.41-32.30) in group 2 (M/P), and 26.56 (15.21-37.70) in group 3 (S/C) (p>0.05). Mean CT values were not significantly different in patients who had radiographic pneumonia, bacterial co-infections, immunocompromised status, or those who were admitted to the PICU compared to children who didn’t have any of these complications.

Conclusion: Novel Influenza A H1N1 respiratory viral load as estimated by PCR CT values didn’t correlate with disease severity in pediatric patients hospitalized at our institution during the 9 months study period. The risk of severe disease was comparable between healthy children and those with comorbidities. It is possible that  disease severity was influenced by host factors & local immune/inflammatory response rather than respiratory viral load.

Subject Category: V. Virology including clinical and basic studies of viral infections, including hepatitis

Hazar Kobayaa, M.D., Pediatrics/Pediatric Infectious Diseases, Children's Hospital of Michigan, Wayne State University, Detroit, MI and Basim Asmar, MD, Pediatrics/ Pediatric Infectious Diseases, Children's Hospital of Michigan, Wayne State University, Detroit, MI


H. Kobayaa, None

B. Asmar, None

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