Influenza symptoms? Antivirals save money and improve outcomes

January 1, 2006

Do benefits of anti-influenza therapy in healthy children justify their cost and adverse effects? If they are justified, should treatment be based on clinical diagnosis or on rapid testing? Should oseltamivir or amantadine be standard therapy? And how does a child's age affect cost effectiveness?

To answer these questions, investigators constructed a decision analysis model, based on published data from antiviral and vaccine trials, to compare the cost-effectiveness of empiric antiviral therapy, test-guided antiviral therapy, and no antiviral therapy for children who have symptoms of influenza. The model was based on hypothetical children who are 2, 7, and 15 years of age and who are seen by a primary care provider within 48 hours of developing symptoms during a local influenza outbreak. The outbreaks studied had varying proportions of influenza A and B.

Compared with no treatment, empiric antiviral therapy results in the greatest quality-adjusted life expectancy in all age groups by shortening the duration of illness and preventing otitis media. Children who are vaccinated against influenza incur lower costs and have a better health outcome-whether or not they are treated.

When influenza B is common, empiric oseltamivir replaces amantadine as the least expensive option in 2-year-olds, although it is less cost-effective in older children, who require a larger dosage (amantadine is inactive against influenza B). In mixed influenza seasons, empiric oseltamivir is the preferred strategy among all three age groups. Rapid influenza testing is not helpful-regardless of which influenza type predominates during a particular season. Under hypothetical conditions, testing is both more expensive and less effective than empiric therapy (Rothberg MB et al. Arch Pediatr Adolesc Med 2005;159:1055).

Commentary The hypothetical patients were all brought to see the provider within 48 hours after symptoms began. Given the availability of telephone triage and over-the-counter remedies, however, how often does that happen? It may be that antiviral therapy is most useful for the second patient in a household, whose illness you can anticipate after observing the "index" sibling.