Influenza (true 'flu) is an infection of the airways caused by the Influenza group of viruses. Influenza occurs most commonly during winter months and can result in symptoms such as fever, cough, sore throat, headache, muscle aches and fatigue. These are usually self limiting but may persist for one to two weeks. The most common complications of influenza are secondary bacterial infections including otitis media (ear infections) and pneumonia. Influenza infection is also highly contagious and is spread from person-to-person by droplets produced when an infected individual coughs or sneezes.
This update reviews the randomised controlled trial evidence of a class of drugs called the neuraminidase inhibitors in treating and preventing influenza in children. Neuraminidase inhibitors work against influenza by preventing viruses from being released from infected cells and subsequently infecting further cells. Oseltamivir (Tamiflu), an oral medication, and zanamivir (Relenza), an inhaled medication, are currently licensed, whilst laninamivir is undergoing Phase III clinical trials. Neuraminidase inhibitors are usually prescribed to patients presenting with flu-like symptoms during epidemic periods to reduce symptoms or prevent spread of the virus.
We included six treatment trials involving 1906 children with clinically suspected influenza and 450 children with influenza diagnosed on rapid influenza testing. Of these 2356 children, 1255 had proven influenza infection confirmed on laboratory testing. We also included three trials of neuraminidase inhibitors for the prevention of influenza, which involved 863 children who had been exposed to influenza.
This review found that treatment with neuraminidase inhibitors was only associated with modest clinical benefit in children with proven influenza. Treatment with oseltamivir or zanamivir shortened the duration of illness in healthy children by about one day. One trial demonstrated that the new neuraminidase inhibitor drug laninamivir reduces duration of illness by almost three days in children with oseltamivir-resistant influenza. The effect of neuraminidase inhibitors in preventing transmission of influenza was also modest; 13 children would need to be treated to prevent one additional case. Neuraminidase inhibitors are generally well tolerated but there will be one extra case of vomiting for every 17 children treated with oseltamivir. Other side effects such as diarrhoea and nausea were no more common in children treated with neuraminidase inhibitors compared to placebo. There is currently no high-quality evidence to support targeted treatment of 'at risk' children (with underlying chronic medical conditions) with neuraminidase inhibitors.