Ministers should review the use of a widely used anti-flu medication, scientists have said after new research has questioned the efficacy of the drug.
The study suggested that Tamiflu, which is used to prevent and treat influenza, shortens flu symptoms by between a day and half a day. But the authors said there is "no good evidence" to support claims that it reduces flu-related hospital admissions or the complications of influenza.
The researchers , from The Cochrane Collaboration and the British Medical Journal (BMJ), also claimed that taking the drug could increase a person's risk of nausea and vomiting.
And when used as a preventative treatment it can stop people developing flu symptoms but may not prevent them from spreading flu to others, the authors said.
The findings of the review may cause further questions to be raised about the Government's stockpile of the drug.
The Department of Health began accumulating Tamiflu in 2006 in response to the increasing concerns about bird flu. Official estimates suggest that ministers have spent £424 million backing up supplies of the flu drug.
"The BMJ and Cochrane issue a joint call to government and health policy decision makers the world over, asking in light of the latest findings from the Cochrane Review, would you make the same recommendations today, choosing to stockpile Tamiflu?" a BMJ spokeswoman said.
Pharmaceutical company Roche said it "fundamentally disagrees" with the latest review.
And the Department of Health said that Tamiflu has a "proven record" of safety, quality and efficacy. But a spokeswoman said that health officials regularly review all published data so will consider the latest Cochrane review "closely".
The researchers reviewed data from 20 clinical study reports on Tamiflu.
They found that taking Tamiflu led to an alleviation in flu-like symptoms an average of 16.7 hours quicker when compared to taking a placebo.
But th ey said that they did not observe any evidence in the reductions of hospital admissions or flu complications such as pneumonia or bronchitis. But peers have criticised this finding, saying that most of the trials in the review were not very precise or reliable in how they defined and recorded the complications.
The researchers also found that taking Tamiflu increased the risk of nausea and vomiting by about 4% in adults and 5% in children.
The study authors wrote: " In prophylactic studies oseltamivir (Tamiflu) reduces the proportion of symptomatic influenza.
"In treatment studies, it also modestly reduces the time to first alleviation of symptoms, but it causes nausea and vomiting and increases the risk of headaches and renal and psychiatric syndromes.
"The evidence of clinically significant effects on complications and viral transmission is limited because of rarity of such events and problems with study design.
"The trade-off between benefits and harms should be borne in mind when making decisions to use oseltamivir for treatment, prophylaxis, or stockpiling."
Cochrane's editor in chief Dr David Tovey said: "We now have the most robust, comprehensive review on 'neuraminidase inhibitors' that exists. Initially thought to reduce hospitalisations and serious complications from influenza, the review highlights that Tamiflu is not proven to do this, and it also seems to lead to harmful effects that were not fully reported in the original publications. This shows the importance of ensuring that trial data are transparent and accessible."
Manufacturers Roche raised concerns about the review.
Roche's UK medical director Dr Daniel Thurley said : " We disagree with the overall conclusions of this report. Roche stands behind the wealth of data for Tamiflu and the decisions of public health agencies worldwide, including the US and European Centres for Disease Control and Prevention and the World Health Organisation.
"The report's methodology is often unclear and inappropriate, and their conclusions could potentially have serious public health implications. Neuraminidase inhibitors are a vital treatment option for patients with influenza."
A Department of Health spokeswoman said: "The UK is recognised by the World Health Organisation as being one of the best prepared countries in the world for a potential flu pandemic. Our stockpile of antivirals is a key part of this.
"Tamiflu is licensed around the world for the treatment of seasonal flu and is a licensed product with a proven record of safety, quality and efficacy. We regularly review all published data and will consider the Cochrane review closely."
Commenting on the study Professor Wendy Barclay, influenza virology expert at Imperial College London, said: "T he report concludes that the drugs did shorten the time to when adults felt better by about one day (16 hours) and in healthy children this was also the case (29 hours).
"Although one day does not sound like a lot, in a disease that lasts only 6 days, it is. In the community this gets people back to work and school, and having the drugs available also serves as a safety net to treat people who get sick enough to go to hospital.
"We should be careful about the message that is now sent to doctors and to the public. Influenza virus infections can lead to death. We have only two drugs with which we can currently treat influenza patients and there is some data to suggest they can save lives.
"It would be awful if, in trying to make a point about the way clinical trials are conducted and reported, the review ended up discouraging doctors from using the only effective anti-influenza drugs we currently have."
"Most of the controversy surrounding these drugs is about whether they should be stockpiled for pandemics. If another pandemic came tomorrow, and the government had no drug with which to treat thousands of influenza infected patients, I imagine there would be a public outcry.
"This new report, taken alongside a lot of other data collected in different settings, does not convince me that the risks of taking Tamiflu or Relenza would outweigh the benefits."