ICAAC: Fewer Secondary Complications with Tamiflu-Treated Kids

SAN FRANSICO, Oct. 2 -- Children who receive Tamiflu (oseltamivir) within one day of influenza diagnosis are half as likely to develop pneumonia as a complication, researchers said here.

Tamiflu also significantly reduced respiratory complications by 39% and hospitalizations by 50%, Dominick A. Iacuzio, Ph.D., of Roche Laboratories in Nutley, N.J., reported at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

His retrospective study of health insurance claims found a significant pneumonia-risk reduction of 52% for children one to two years old and 57% for those six to 12 years old (relative risk odds ratio 0.483 and 0.428). Children from three to five did not have a significant risk reduction (37%).

Respiratory illness risk likewise was significantly reduced:

• 31% for children one to two years old,
• 26% for children three to five years old, and
• 20% for children six to 12 years old.

Hospitalizations for respiratory illness and for any reason dropped significantly as well (91%, 95% CI 0.01 to 0.71 and 50%, 95% CI 0.31 to 0.81) while pneumonia hospitalizations fell by 43%.

The likelihood of otitis media ear infection as a complication significantly decreased as well:

• 32% for children one to two years old,
• 29% for children three to five years old, and
• 29% for children six to 12 years old.

The study analyzed insurance claim data in the Medstat MarketScan Research Database for the first claim diagnosis of influenza. It included data from 7,914 children ages 12 and under who were treated with Tamiflu, propensity matched to the same number of children with an influenza diagnosis who did not receive the antiviral.

While 33% of the children who took Tamiflu had received an antibiotic as well, more of those who did not have Tamiflu received antibiotics (37.8%). The kids with no antiviral claim in the database also had more emergency room visits.

The data spanned five influenza seasons from Oct. 1, 2005, to March 31 2005. Individuals not continuously insured from the three months prior to the month after the first influenza claim were excluded.

Relative risk calculations controlled for influenza season, age, gender, preexisting comorbidities, influenza vaccination status and other baseline characteristics.

The analysis did not include babies less than a year old since Tamiflu is only indicated for the treatment of influenza in adults and children at least one year old who receive the medication within the first 48 hours of the onset of symptoms.

The problem is that for pediatric patients "you simply can't tell what's influenza" to make the rapid diagnosis needed for prescription of Tamiflu, said J. Owen Hendley, M.D., of the University of Virginia in Charlottesville, who commented on the study.

Dr. Hendley said the best option is to use the flu vaccine to prevent influenza in the first place.

The CDC recommends that people at high risk for complications from the flu, including children ages six months to about five years old, should be vaccinated against influenza each year.

Influenza affects as many as 40 million Americans annually, with children two to three times more likely to be affected than adults. Community-acquired pneumonia occurs in 34 to 40 per 1,000 children in the United States each year, which makes it one of the most common serious infections in children.

Authors of the study are employees of Roche Laboratories and Thomson Medstat.