Nearly half of pediatric influenza deaths occur in otherwise healthy children, according to an 8-year Centers for Disease Control and Prevention study published online October 28 in Pediatrics.

“[T]hese data, which reveal that any child can be at risk of influenza-associated death regardless of age or high-risk medical conditions, support the recommendation that all children ≥6 months of age receive annual vaccination,” Karen K. Wong, MD, MPH, from the Epidemic Intelligence Service assigned to the Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, and colleagues write. They note that the national coverage rate (52% in 2011-2012) remains far below the Healthy People 2010 objective of 80%.

The investigators reviewed data for 830 pediatric influenza-related deaths that occurred between October 2004 and September 2012. Of the 794 children with an available medical record, 341 (43%) had no high-risk medical conditions such as neurologic disorders, asthma, or diseases of the heart, kidney, liver, or immune system, and 453 (57%) did. Among the entire study population, the median age of death was 7 years (interquartile range [IQR], 1 – 12 years), with 35% of cases occurring before hospital admission.

As expected, the study data confirmed the increased risk for complications, including mortality, among children with comorbidities: 33% of high-risk deaths occurred in children with neurologic disorders, and 12% had genetic or chromosomal disorders.

However, researchers also found that otherwise healthy children were almost twice as likely to die before hospital admission as their high-risk counterparts (relative risk [RR], 1.9; 95% confidence interval [CI], 1.6 – 2.4) and were 1.6 times more likely to die within 3 days of symptom onset (95% CI, 1.3 – 2.0).Although the cause remains unclear, a doubled prevalence of bacterial coinfection may have factored in the observed acceleration of clinical course (relative risk [RR], 2.0; 95% CI, 1.5 – 2.5), the authors write.

Otherwise healthy children were also more likely to be younger than 5 years (RR, 1.3; 95% CI, 1.1 – 1.6; P < .001), with a median age of 5 years (interquartile range [IQR], 1 – 11 years), compared with 8 years (IQR, 3 – 13 years) in the high-risk group.

According to the authors, the findings underscore the need for clinicians to be more aggressive with antiviral therapy.

“[I]influenza antiviral medications can reduce the severity of illness and complications associated with influenza virus infection…. [H]owever, antiviral treatment was reported in less than half of the children who died during the 2010-2011 and 2011-2012 seasons in this study,” the authors point out.

Children with signs or symptoms of severe or progressive illness and those who are hospitalized should be started on antivirals without waiting for laboratory results, even if they have no other risk factors for influenza-related complications, the authors write. Oseltamivir can be used in infants as young as 2 weeks, they note. In addition, antivirals are recommended regardless of illness severity for children younger than 2 years and for those with high-risk medical conditions.

“The potential for severe outcomes from influenza should be recognized in all children, both those with conditions that place them at higher risk of influenza-associated complications as well as healthy children,” the authors conclude.