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Three Part Question

In [pediatric patients ages 1-12 with clinical influenza-like symptoms], does [early treatment with Tamiflu] reduce the [incidence of secondary pneumonia]?

Clinical Scenario

An eighteen month old boy presents with flu-like symptoms for one day. Other than shortening the length of symptoms, does antiviral therapy prevent risks of secondary pneumonia?

Search Strategy

Ovid MEDLINE 1996 to October Week 1 2009
(exp oseltamivir) AND (exp influenza) AND (exp pneumonia)

Search Outcome

Thirteen papers were retrieved from the search. Only one paper studied secondary pneumonia in patients < 13 years old. Details of this paper are shown in Table 1.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Barr, CE, Schulman, K, Iacuzio, D, and Bradley JS 2007 US	25,144 children ages 1-12 with clinical symptoms of influenza. 18% received oseltamivir within 48 hours of symptom onset.	Retrospective cohort database review. Outcome was occurrence of pneumonia within 14 days of onset of influenza	Occurrence of pneumonia within 14 days of onset of influenza The overall relative risk reduction of being diagnosed with pneumonia for children in the treatment group was 0.48 (95% CI: 0.33, 0.7).	Though an overall relative risk reduction of 0.48 is impressive, only 0.7% of the treatment group and 1.4% of the control group were diagnosed with pneumonia. This suggests that secondary pneumonia is a rare complication regardless of antiviral therapy. The number needed to treat with tamiflu to prevent one pneumonia was 140 by my calculation.	Retrospective, relied on ICD-9 codes, clinical diagnosis, paid by Roche

Comment(s)

The current epidemic of H1N1 influenza has increased awareness of antiviral therapy for influenza infections. Oseltamivir (Tamiflu) is one of two drugs that are effective in the treatment of H1N1 influenza. In previous studies of pediatric patients, receiving oseltamivir in the first 48 hours of symptoms decreased duration of illness by 1.5 days. A new diagnosis of otitis media and the incidence of antibiotic prescriptions were also decreased with oseltamivir treatment of influenza . In older patients, ages 13-97 years, lower respiratory tract complications were decreased . No previous studies, however, have examined the impact of oseltamivir on preventing the incidence of pneumonia after influenza in children. This short review examines the effect of oseltamivir on the risk of a secondary pneumonia in children with clinically diagnosed influenza. A retrospective database cohort review of children ages 1-12 is discussed. The overall relative risk reduction of being diagnosed with pneumonia for children in the treatment group was 0.48 (95% CI: 0.33, 0.7). Though an overall relative risk reduction of 0.48 is impressive, only 0.7% of the treatment group and 1.4% of the control group were diagnosed with pneumonia. This suggests that secondary pneumonia is a rare complication regardless of antiviral therapy. The number needed to treat with tamiflu to prevent one pneumonia was 140 by my calculation. Of note, this study excluded hospitalized patients and patients presenting with both influenza and pneumonia. The incidence of influenza complications is likely to be higher than in a healthy population. Due to the low incidence of secondary pneumonia in healthy children, I feel this study does not support routine use of oseltamivir to prevent this complication of influenza. However, children at higher risk of influenza complications may benefit from oseltamivir though this population has not been studied directly.

Clinical Bottom Line

Oseltamivir appears to reduce the incidence of pneumonia following clinically diagnosed influenza in children ages 1-12. However, the incidence of pneumonia is quite low in healthy children, thus, it is appropriate to reserve use of oseltamivir for higher risk populations

References

1. Barr, CE, Schulman, K, Iacuzio, D, and Bradley JS Effect of oseltamivir on the risk of pneumonia and use of health care services in children with clinically diagnosed influenza Current Medical Research and Opinions 2007; 23:523-53.