In light of a recent study from The Cochrane Collaboration saying there is no good evidence supporting that Tamiflu reduces admissions to hospital or complications of influenza, the global healthcare research network and the BMJ are asking government and health policy decision makers around the world if they still recommend stockpiling Tamiflu in case of an influenza pandemic.

Avian, swine flu protection

Previous claims about the effectiveness of Tamiflu against complications were a key factor in decisions made by governments around the world to stockpile these drugs in case of a pandemic. The US has spent more than $1.3 billion buying a strategic reserve of antivirals, while the UK government has spent almost GBP424 million ($711 million) for a stockpile of about 40 million doses.

The UK's National Health Service website contains a section dedicated to avian influenza. It says: "certain antiviral medications have been stockpiled for use in the event of an outbreak. Oseltamivir (Tamiflu), Zanamivir (Relenza) and Peramivir (Actrapid) may help reduce the severity of the condition, prevent complications and help improve the chance of survival".

The worldwide use of Tamiflu has increased dramatically since the outbreak of H1N1 virus (swine flu) in April 2009. It was initially believed that it would reduce hospital admissions. Although the review has confirmed small benefits on symptom relief (the drug can shorten flu symptoms by half a day), there is little to justify that it reduces hospital admissions or the risk of developing confirmed pneumonia, the study says. Along with the evidence of harms from the medication, it raises the question of whether global stockpiling of the drugs is still justifiable given the lack of reliable evidence to support the original claims.

Insufficient grounds to support Tamiflu prevents person-to-person flu spread

Evidence from treatment trials confirms increased risk of suffering from nausea and vomiting, the authors say. When Tamiflu was used in prevention trials, there was an increased risk of headaches, psychiatric disturbances and renal events. Although when used as a preventive treatment, the drug can reduce the risk of people suffering symptomatic influenza, it is unproven that it can stop people carrying the influenza virus and spreading it to others.

The study, "Neuraminidae inhibitors for preventing and treating influenza in healthy adults and children," is based on full internal reports of 20 Tamiflu and 26 Relenza (zanamivir) trials. Evidence suggests there are insufficient grounds to support the use of Tamiflu in preventing person-to-person spread of influenza, the authors state.

Disagreement, however, has emerged regarding the study's findings, and there are claims that it could have "serious implications for public health". Others have noted that some relief from symptoms is better than none at all, while others still have said the findings need to be reviewed.