Abstract
Although the influenza vaccine is relatively safe and effective, serious complications can develop in rare cases. We encountered two cases of interstitial pneumonia that developed after vaccination during the 2014-2015 influenza season. Overall, nine cases, including the two presented here, have been recorded in PubMed and the Cochrane library; eight patients were treated with corticosteroids, and all nine survived, suggesting a good prognosis. Interstitial pneumonia is rare; however, we found an increase in its incidence after 2009. Therefore, clinicians must be aware of the possibility of this complication and duly educate all patients in advance.