Complications from influenzalike illnesses occur in one-third of children

In an attempt to identify those at risk for serious complications of influenza, investigators analyzed outcomes for 241 children who presented to the emergency department, met the CDC definition of influenzalike illness (ILI) – fever and sore throat or cough – and had moderate to severe illness based on a medical decision to obtain a venipuncture and multiplex polymerase chain reaction (PCR) respiratory viral testing at the time of the visit. While influenza was confirmed in 25% (80% with influenza A), many other viral respiratory pathogens also were identified, confirming that ILI is not specific for influenza in children. More than one virus was detected in 12%. A chronic medical condition was noted in about one-half, most commonly neurologic and neuromuscular diseases or asthma, and complications including pneumonia and respiratory failure occurred in 30% of those with influenza and 35% with non-influenza viral infection.

Consistent with American Academy of Pediatrics and the Centers for Disease Control and Prevention guidelines, the authors recommend empiric oseltamivir for a child with influenzalike illness who has a condition that places them at risk for influenza complications, particularly if the suspected agent is the pandemic H1N1 virus. However, the data highlight the difficulty in identifying all children who may benefit from oseltamivir therapy, especially given that the majority of children with ILI don’t have influenza, oseltamivir therapy is best initiated within 48 hours of onset of symptoms, the most readily available test (rapid influenza testing) generally lacks sensitivity to identify those with influenza, and PCR testing is expensive and not available in many hospital emergency rooms.

Approximately half of the study patients had a history of influenza vaccine, and it is unclear whether this represented one or two doses in the younger patients. The results underscore the importance of influenza vaccine, and this year the AAP has issued a preference for the nasal live attenuated vaccine for any child aged 2-8 years who doesn’t have an underlying contraindication – emphasizing that vaccination should not be delayed in order to obtain a specific product for either dose.

Dr. Mary Anne Jackson is director of the division of infectious diseases and associate chair of community and regional pediatric collaboration at Children’s Mercy Hospital & Clinics, and professor of pediatrics at University of Missouri–Kansas City. She has no disclosures.