Hundreds of millions of pounds may have been wasted on a drug for flu that works no better than paracetamol, a landmark analysis has said.
The UK has spent £473m on Tamiflu, which is stockpiled by governments globally to prepare for flu pandemics.
The Cochrane Collaboration claimed the drug did not prevent the spread of flu or reduce dangerous complications, and only slightly helped symptoms. The manufacturers Roche and other experts say the analysis is flawed
The antiviral drug Tamiflu was stockpiled from 2006 in the UK when some agencies were predicting that a pandemic of bird flu could kill up to 750,000 people in Britain. Similar decisions were made in other countries.
The drug was widely prescribed during the swine flu outbreak in 2009.
Drug companies do not publish all their research data. This report is the result of a colossal fight for the previously hidden data into the effectiveness and side-effects of Tamiflu.
It concluded that the drug reduced the persistence of flu symptoms from seven days to 6.3 days in adults and to 5.8 days in children. But the report's authors said drugs such as paracetamol could have a similar impact.
On claims that the drug prevented complications such as pneumonia developing, Cochrane suggested the trials were so poor there was "no visible effect".