Initial unsolicited misuse report received from the literature on 27-Sep-2016. This case is linked to 2016SA181196, 2016SA181234, 2016SA181235, 2016SA181236, 2016SA181237, 2016SA181238, 2016SA181239, 2016SA181240, 2016SA181241, 2016SA181242, 2016SA181243, 2016SA181244, 2016SA181245, 2016SA181246, 2016SA181247, 2016SA181248, 2016SA181249, 2016SA181250, 2016SA181251, 2016SA181252, 2016SA181260 (same literature). The following is verbatim from the article: Introduction there have been isolated case reports of medication product mix-ups involving insulin unintentionally given to patients when the intent was to administer vaccines. Information on how and why these types of errors occur is limited. Objective To describe incidents of unintentional administration of insulin instead of influenza vaccine and identify possible causes for errors. Methods we describe a 2014 investigation of an apparent mix-up where a cluster of five adult patients unintentionally received insulin instead of influenza vaccine. We also searched Centers for Disease Control and Prevention (CDC) and US Food and Drug Administration (FDA) vaccine and drug safety monitoring databases from January 2005 to April 2015 in order to identify other incidents. We classified cases as either 'highly suggestive' or 'suggestive' of insulin and influenza vaccine mix-ups. Results Investigation of the primary cluster incident revealed deviations from recommended practices for storage, handling, preparation, and administration of drugs and vaccines; the five cases were classified as highly suggestive of insulin and influenza vaccine mix-ups. Our search of CDC and FDA vaccine and drug safety monitoring databases identified an additional two highly suggestive and 15 suggestive cases, for a total of 22 cases (7 highly suggestive and 15 suggestive) during the 10-year study period. Conclusion Insulin and vaccine mix-ups have the potential to cause serious harm to patients, and are preventable with proper training and application of standards. Our investigation indicated that improper storage including inadequate segregation of insulin and influenza vaccine products in clearly labeled containers or bins lack of standardized procedures for confirming the contents of vials, and decreased vigilance in preparation and administration likely contributed to the primary cluster incident. This case involves a 93-year-old female patient who was administered insulin NOS injection (manufacturer: other) (batch number, expiry date, route and site of administration: not reported) instead of receiving a dose of INFLUENZA VACCINE (manufacturer: unknown) on an unspecified date in 2009. Patient had no known history of diabetes mellitus. Patient's other medical history and concomitant medications were not reported. On an unspecified date in 2009, immediate post administration of insulin, the patient felt ill and blood glucose close to 0 mg/dL. On an unknown date the patient was hospitalized. It was a case of wrong drug administered (unintentional administration of insulin instead of influenza). Other laboratory was not reported. Corrective treatment was not reported. On an unknown date, the patient was recovered from the event. Discharge information was not reported. List of documents held by sender: none. Sender's Comments: This case corresponds to a poorly documented literature case with mention of unintentional administration of insulin instead of influenza vaccine. The reported events are consistent with the diagnosis of hypoglycemia secondary to accidental insulin administration; however influenza vaccine was not administered in this case.