Tamiflu alone won't work in bird flu pandemic

Jan 19 2006

In a review published this week a warning has been issued against the apparent reliance by most countries on the drug Tamiflu to combat a bird flu pandemic.

The review says there is no evidence that Tamiflu, the drug being stockpiled by Britain, the United States and Europe, will work if a flu pandemic takes off in humans.

According to Tom Jefferson, author of the review, none of the four existing drugs against influenza have much effect.

The authors strongly warn against relying on drugs to stamp out a potential avian flu pandemic, and believe complacency will deter the use of public health measures such as hygiene and isolation, to stop the spread of infection.

Jefferson, says though he hopes that Tamiflu and Relenza will save lives in a pandemic, they have not to date been shown to reduce mortality among the few flu victims who have taken them.

He says relying on a single solution is suicidal, as there is simply no data on the use of the two drugs in a pandemic situation.

The review says the use of the drugs should not be considered in a pandemic "without concomitant measures, such as barriers, distance and personal hygiene".

The authors say that while the drugs might reduce patients' symptoms, the use of Tamiflu could actually increase the spread of the flu virus, because if people take the drug and then have fewer symptoms they may go to work and further spread the potentially lethal virus.

In the review Dr Jefferson and colleagues from the Cochrane Vaccines Field looked at all the evidence from trials on the efficacy of all four flu drugs, Tamiflu and Relenza and two older drugs from a different class, Amantadine and Rimantadine.

Amantadine and Rimantadine are a problem as their use has led to the emergence of resistant flu strains and they cause unpleasant side-effects, such as hallucinations.

The study, part-funded by the Department of Health, recommends that none of the four should be used for the treatment of ordinary winter flu.

Tamiflu and Relenza reduce the severity of real influenza, but do not work on viral infections with similar symptoms, which cannot be distinguished by the GP from real flu without tests.

By the time tests are done, Relenza and Tamiflu are no use, because they must be given within 48 hours of the onset of flu.

The reviewers firmly believe the two drugs should be kept for pandemic use only, where it will be obvious that the cases doctors see will be genuine influenza.

The review could very well lead to a change of policy from the World Health Organisation, which recommends countries to use antiviral flu drugs in times of ordinary seasonal flu outbreaks so that health workers can become familiar with their use in case of a pandemic.

The Department of Health, which has ordered 14.6m courses of Tamiflu, has disputed the claims of the review saying it is misleading.

It does however admit it is looking for a "back-up" strategy.

The review is published in the Lancet medical journal.