SAN DIEGO — Respiratory syncytial virus was the most common virus detected in young children with bronchiolitis, but nearly 40% were infected with other viruses, results from a single-center study showed.
“The results suggest that further study is warranted to learn more about the potential impact of viral pathogens associated with bronchiolitis,” Hilary Stempel said at the annual meeting of the Infectious Diseases Society of America.
Ms. Stempel, a clinical research associate in infectious diseases with Children's Hospital and Regional Medical Center, Seattle, said that she and her associates undertook the study because guidelines from the American Academy of Pediatrics recommend that the diagnosis of bronchiolitis should be made on the basis of history and physical, and that clinicians should not routinely order laboratory tests for the diagnosis (Pediatrics 2006;118:1774-93).
The rationale for this position, according to the guidelines, is that “the knowledge gained from such testing rarely alters management decisions or outcomes for the vast majority of children with clinically diagnosed bronchiolitis.”
However, the guidelines do state that “virologic testing may be useful when cohorting of patients is feasible.”
That particular statement interested the researchers at the hospital, where “patient cohorting is still a necessity,” Ms. Stempel said. “So we decided to explore the implications of viral testing for children with bronchiolitis.”
Researchers collected residual nasal wash specimens from 189 children aged 0-3 years who were evaluated for bronchiolitis from October 2003 through April 2004. All specimens were evaluated with quantitative real time polymerase chain reaction testing and fluorescent antibody assay.
The median age of the 189 children was 7 months, 54% were male, and 26% had an underlying disease such as asthma or a cardiac condition.
Most samples (72%) were acquired from the general pediatric ward, while 21% were acquired from the emergency department, and 7% from the intensive care unit.
Ms. Stempel reported that a total of 220 respiratory viral pathogens were detected in 177 of the 189 children (94%). The majority of the 220 viruses were RSV (145), followed by adenovirus (28), human metapneumovirus (hMPV) (20), coronavirus (14), parainfluenza (12) and influenza (1).
Forty-three samples contained two or more viruses. Of these, 35 (81%) involved RSV. Other coinfections included hMPV and parainfluenza (4 samples), hMPV and adenovirus (3 samples) and parainfluenza and adenovirus (1 sample).
Limitations of the study include its retrospective design and the fact that rhinovirus assay was not performed. Also, “the study ended in April 2004 and did not extend through the entire parainfluenza season,” Ms. Stempel said. “This may have lowered the number of parainfluenza infections that we detected.”
Ms. Stempel disclosed that one of the study coauthors, Dr. Janet A. Englund, has received research support and consulting fees from MedImmune and Sanofi Pasteur.
'We decided to explore the implications of viral testing for children with bronchiolitis.' MS. STEMPEL