 On 8 December 2009 , the Cochrane Collaboration , which reviews medical evidence , announced in a review published in BMJ that it had reversed its previous findings that the antiviral drugs oseltamivir ( Tamiflu ) and zanamivir ( Relenza ) can ward off pneumonia and other serious conditions linked to influenza . They reported that an analysis of 20 studies showed oseltamivir offered mild benefits for healthy adults if taken within 24 hours of onset of symptoms , but found no clear evidence it prevented lower respiratory tract infections or other complications of influenza . Their published finding relates only to its use in healthy adults with influenza ; they say nothing about its use in patients judged to be at high risk of complications ( pregnant women , children under five and those with underlying medical conditions ) , and uncertainty over its role in reducing complications in healthy adults may still leave it as a useful drug for reducing the duration of symptoms . The drugs might eventually be demonstrated to be effective against flu @-@ related complications ; in general , the Cochrane Collaboration concluded " <unk> of good data " . 
