Research suggests that taking aspirin following transient ischaemic attack (TIA) or stroke can reduce the risk of a secondary stroke by 13%. However, observational studies suggest that the short-term benefits might be much higher.
Therefore, researchers pooled and randomised data from 15,778 patients to look at the very early effects.
They found that taking aspirin reduced the risk and severity of recurrent stroke in the first six weeks compared with control. But the greatest effect was observed in the first two weeks, particularly following TIA or minor stroke, where it reduced the risk of disabling or fatal stroke by over 90%.
Reporting their findings in The Lancet (online, 18 May 2016)
, the researchers say that previous studies underestimated the beneficial effects of urgent aspirin treatment and public education campaigns should encourage people to self-administer aspirin if they suspect TIA symptoms.
 Rothwell PM, Algra A, Chen Z et al. Effects of aspirin on risk and severity of early recurrent stroke after transient ischaemic attack and ischaemic stroke: time-course analysis of randomised trials. The Lancet 2016. doi: 10.1016/S0140-6736(16)30468-8