The purpose of this guidance document is to inform physicians and other health care practitioners of an increased risk of influenza outbreaks in long-term care facilities (LTCF) during the 2014-2015 influenza season in Canada, and to provide recommendations for adjustment to LTCF outbreak control measures on the basis of documented vaccine mismatch. Influenza seasons dominated by A(H3N2) viruses are typically associated with greater morbidity and mortality than other types/subtypes of influenza, especially in the elderly (1-3). Significant genetic and antigenic differences have been identified so far in 2014-2015 among circulating A(H3N2) viruses compared with the 2014-2015 H3N2 vaccine component chosen by the World Health Organization (WHO) for the northern hemisphere (4,5). These differences between circulating viruses and the vaccine strain (called ‘antigenic drift’ or ‘vaccine mismatch’) are anticipated to have important implications for reduced vaccine protection this season. Consequently, adjunct protective measures, such as antiviral medications, may require greater emphasis and expanded use in responding to LTCF outbreaks this season.