Neuraminidase inhibitors for preventing and treating influenza in children.
BACKGROUND
During epidemic years, influenza attack rates in children exceed 40%. Options for prevention and treatment include the neuraminidase inhibitors: zanamivir and oseltamivir.


OBJECTIVE
To assess the efficacy, safety and tolerability of neuraminidase inhibitors in the treatment and prevention of influenza infection in children.


METHODS
We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005); MEDLINE (1966 to April 2005); EMBASE (January 1980 to December 2004); the on-line GlaxoSmithKline Clinical Trials Register; the on-line Roche Clinical Trial Protocol Registry and Clinical Trial Results Database (August 2005); and reference lists of articles. We also scrutinised web sites of European and US regulatory bodies and contacted manufacturers and authors.


METHODS
Double-blind, randomised, controlled trials comparing neuraminidase inhibitors with placebo or other antiviral drugs in children less than 12 years of age. Additional safety and tolerability data from other sources were also included.


METHODS
Four authors applied the inclusion criteria to the retrieved studies, assessed trial quality and extracted data. Data were analysed separately for oseltamivir and zanamivir.


RESULTS
Three trials involving 1500 children with a clinical case definition of influenza were included, of whom 977 had laboratory-confirmed influenza. Overall, trial quality was good. Oseltamivir reduced the median duration of illness by 26% (36 hours) in healthy children with laboratory-confirmed influenza (P value less than 0.0001). The reduction was only 7.7% (10 hours) in 'at risk' (asthmatic) children, and this did not reach statistical significance (P value = 0.54). Zanamivir reduced the median duration of illness by 24% (1.25 days) in healthy children with laboratory-confirmed influenza (P value less than 0.001). No data in 'at risk' children were available. Only oseltamivir produced a significant reduction in the complications of influenza (particularly otitis media), although there was a trend to benefit for zanamivir. We identified one randomised, controlled trial of oseltamivir for the prevention of influenza transmission in households, reporting data from 222 paediatric contacts. Where index cases had laboratory-confirmed influenza, a protective efficacy of 55% was observed, but this did not reach statistical significance (P value = 0.089). The adverse events profile of zanamivir was no worse than placebo, but vomiting was more common in children treated with oseltamivir.


CONCLUSIONS
Neuraminidase inhibitors are effective in shortening illness duration in healthy children with influenza, but efficacy in 'at risk' children remains to be proven. Oseltamivir is also effective in reducing the incidence of secondary complications, and may be effective for influenza prophylaxis.
Matheson
N J
NJ
Harnden
A R
AR
Perera
R
R
Sheikh
A
A
Symmonds-Abrahams
M
M
D000081:Acetamides / Q000009:adverse effects / Q000627:therapeutic use; D000998:Antiviral Agents / Q000627:therapeutic use*; D002648:Child; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D006801:Humans; D007251:Influenza, Human / Q000188:drug therapy*; D009439:Neuraminidase / Q000037:antagonists & inhibitors*; D053139:Oseltamivir / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic; D012794:Sialic Acids / Q000009:adverse effects / Q000627:therapeutic use; D053243:Zanamivir / Q000627:therapeutic use
D000081:Acetamides; D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D012794:Sialic Acids; D053139:Oseltamivir; D009439:Neuraminidase; D053243:Zanamivir