Increased Severity of H1N1 in Children and Adults With Sickle Cell Disease: Presented at ASH
By Betty S. Riggs
NEW ORLEANS -- December 8, 2009 -- Infection with influenza A (H1N1) in patients with sickle cell disease (SCD) is more severe than infection with seasonal influenza, resulting in increased need for intensive care and increased risk for acute chest syndrome, according to a study presented here at the American Society of Hematology (ASH) 51st Annual Meeting and Exposition.
“Our findings underscore that receiving a vaccination against H1N1 influenza, in addition to seasonal influenza, is extremely important for the health and safety of children and young adults with sickle cell disease,” said John J. Strouse, MD, Division of Pediatric Hematology, Johns Hopkins University School of Medicine, Baltimore, Maryland, on December 7.
To compare the relative severity of H1N1 versus seasonal influenza A and B in young patients with sickle cell disease, Dr. Strouse and colleagues used discharge, laboratory, and billing databases, as well as electronic and paper records, to evaluate laboratory confirmed cases of influenza in infants, children, and adolescents (up to age 21) with sickle cell disease from September 1993 to November 2009.
All respiratory samples positive for influenza A after May 1, 2009, were tested for H1N1 using a real-time reverse transcription polymerase chain reaction assay. Acute chest syndrome was diagnosed based on a new pulmonary infiltrate and fever, shortness of breath, chest pain, or increased respiratory rate.
Of the patients with sickle cell and influenza, 90 had seasonal influenza and 28 had H1N1. The average age in the seasonal group was 4.3 years and 8.7 years in the H1N1 group (P = .009).
Clinical symptoms, such as fever, cough, and emesis were similar between groups. However, patients with H1N1 influenza were more likely to have asthma (58%) than those with seasonal influenza (23%; P = .001); acute chest syndrome (32% vs 12%; P = .02); to require intensive care (14% vs 2%; P = .03); blood transfusion (31% vs 13%; P = .03); and ventilator support (11% vs 0%; P = .02).
Researchers observed that older age (P = .03) and H1N1 influenza versus seasonal influenza (P = .11) were associated with increased risk of intensive care and acute chest syndrome.
Funding for this study was provided by the Doris Duke Charitable Foundation, and the National Heart, Lung, and Blood Institute.
[Presentation title: Increased Severity of Pandemic H1N1 Influenza in Children and Young Adults With Sickle Cell Disease. Abstract 264]
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