Lam F, Shih CC, Chen TL, et al. - Among geriatric stroke patients who received influenza vaccination (IV), researchers assessed the risk of urticaria. They selected 9,890 stroke patients who received IV and also selected 9,890 propensity score-matched stroke patients who did not receive IV, from a cohort of 192,728 patients with newly diagnosed stroke (aged > 65 years) identified from 23 million individuals in Taiwan’s National Health Insurance between 2000 and 2008. Participants were observed for 1 year. Among both sexes, patients 65–84 years of age, patients with comorbid medical conditions, and various time intervals of follow-up, the investigators detected an increased risk of urticaria in stroke patients with IV. A very high risk of urticaria was observed in vaccinated stroke patients with hemorrhage and those who received intensive care vs those without IV. Findings may thus be indicative of a link between IV receipt and increased risk of urticaria in stroke patients. The researchers could not conclude causality from their findings due to study limitations.