Of 3610 patients with nontraumatic cervical artery dissection (mean age, 52 years), 265 patients (7%) had had one or more influenza-like illnesses during their case periods. In adjusted models, patients were more likely to have influenza-like illness within 15, 30, and 90 days before cervical artery dissection compared with the same interval 1 and 2 years before dissection.Conclusions: Influenza-like illness might increase the risk of cervical artery dissection for 15 days and possibly for #3 months.Commentary: Dissection of the cervical arteries without a history of major trauma is an important nonatherosclerotic cause of ischemic stroke in patients aged 15 to 45 years. The possible risk factors for cervical artery dissection without major trauma include connective tissue disorders, such as Ehlers-Danlos syndrome type IV, minor trauma to the head or neck, such as coughing and sneezing, and recent infection. Inflammatory markers such as the white blood cell count and C-reactive protein have also been associated with cervical artery dissection.Influenza-like illness has been used by the Centers for Disease Control and Prevention and the Department of Defense to monitor and study emerging influenza. Influenza-like illnesses have been suggested as a trigger of ischemic stroke. The association was especially strong in individuals aged #45 years. Influenza-like illness might increase the risk of cervical artery dissection for 15 days and, potentially, for #3 months. Awareness of the potential for stroke after influenza might lead to clinical trials testing short-term vascular protective strategies, such as statins or antiplatelet agents, after the onset of influenza.What to take away from this provocative study? Be careful when you sneeze or cough and perhaps start taking a baby aspirin after the flu for a few weeks? However, I think all of us are more concerned with a different virus at present.