How so? The antiviral may not prevent complications from influenza in healthy adults, according to a review by an independent research group that reversed its previous findings that Tamiflu defended against and other deadly conditions linked to the disease.
An analysis of 20 studies by the Cochrane Collaboration showed Tamiflu offered mild benefits for healthy adults and found no clear evidence it prevented lower respiratory tract infections or complications of influenza. The group concluded that Tamiflu “should not be used in routine control of seasonal influenza" and urged that independent randomized trials should be conducted to resolve the "uncertainties."
The review, which was published in the British Medical Journal (see here) and updated a 2005 analysis, excluded eight studies funded by Roche that haven’t been published and whose full data wasn’t given to the researchers to verify independently. The exclusion reversed the group’s earlier finding that Tamiflu protects against complications.
In an editorial, Fiona Godlee, BMJ's editor, notes that governments around the world “have spent billions of pounds on a drug that the scientific community now finds itself unable to judge”.
Accompanying all this is a remarkable play-by-play account of how the lead researcher on the 2005 analysis attempted to verify the original report, but ran into a stonewalling Roche. The episode "exposed a complex interplay between politics, public health planning, availability of trial data, publishing, and drug regulation," writes BMJ's Deborah Cohen. This is must reading - look here. And Roche offered responses to the Cochrane group and BMJ here and here.