Introduction: A primary mission of the U.S. Centers for Disease Control and Prevention's (CDC) is promoting immunization against seasonal influenza. As with most education efforts, CDC's influenza-related communications are often informed by formative research.

Methods: A qualitative meta-analysis of 29 unpublished, primarily qualitative CDC-sponsored studies related to flu and flu vaccination knowledge, attitudes and beliefs (KABs). The studies, undertaken between 2000 and 2013, involved focus groups, in-depth interviews, message testing and surveys. Some involved health care professionals, while others involved members of the public, including sub-populations at risk for severe illness.

Findings: The themes that emerged suggested progress in terms of KABs related to influenza and influenza vaccination, but also the persistence of many barriers to vaccine acceptance. With respect to the public, recurring themes included limited understanding of influenza and immunization recommendations, indications of greater sub-group recognition of the value of flu vaccination, continued resistance to vaccination among many, and overestimation of the effectiveness of non-vaccine measures. Seven cognitive facilitators of vaccination were identified in the studies along with six cognitive barriers. For health care providers, the analysis suggests greater knowledge and more favorable beliefs, but many misperceptions persist and are similar to those held by the public. KABs often differed by type or category of health care provider.

Conclusions: The themes identified in this qualitative analysis illustrate the difficulty in changing KABs related to influenza and influenza vaccine, particularly on the scope and scale needed to greatly improve uptake. Even with an influenza pandemic and more vaccine options available, public and some health care provider perceptions and beliefs are difficult and slow to change. This meta-analysis does, however, provide important insights from previously unpublished information that can help those who are promoting influenza vaccination to health care providers, the general public and specific populations within the general population.