Systematic review of factors influencing seasonal influenza vaccine uptake among health care workers

Abstract

Introduction: Influenza is one of the commonest infectious diseases among human beings. The annual attack rates were 5-10% and 20-30% in adult and children respectively around the world. Fortunately, this is a vaccine preventable disease. Vaccinating health care workers can reduce risk of infection among themselves so as to maintain the availability of health care services. This can also prevent nosocomial infections and associated morbidity and mortality of their patients. The World Health Organization recommended 60% influenza vaccination coverage by 2006 in high risk groups and targeted 75% by 2010. However, the vaccine uptake rate among health care workers is still low globally. The vaccination coverage is in Western Europe 20-40%, in Hong Kong 30%, in Australia 16-60% and in the United States 63.5%. This systematic review aims at identifying the factors influencing influenza vaccine uptake among health care workers which can help formulation of future vaccination strategies so as to protect health care workers themselves and their patients.

Methods: Electronic databases (PubMed, MEDLINE and eKG) of journal articles published after January 2011 using title and keywords related to health care workers and influenza vaccination uptake were searched. Predefined inclusion and exclusion criteria were applied. Data were extracted and quality was assessed from the eligible studies using individualized data extraction form and quality assessment form by two reviewers. The reasons of vaccination acceptance and declination were divided into different categories. A score was given to each category according to the percentage of respondents stating that as an important influencing factor. The factor with higher score indicated the more important it is. The predictive factors positively associated with vaccination acceptance were retrieved from results of multivariate logistic regression models of the studies which had an odd ratio greater than one. The PRISMA statement is used to guide the methodology and reporting of the studies.

Results: Nine eligible studies were finally identified. The studies reviewed found that the reasons behind low seasonal influenza vaccination uptake rate among health care workers are complex and made up by both perceptual and organizational factors. For factors of influenza vaccination acceptance, self protection, risk perception, and protection of patients were identified as the most important. For factors of influenza declination, concern of vaccine side effects, lack of concern, and doubts of vaccine safety and efficacy showed the greatest influence. Convenient vaccination location and time was suggested to be the strongest predictive factor which positively associated with future vaccination uptake.

Conclusion: As influenza vaccination is an effective measure to prevent infection among health care workers and nosocomial infection of their patients, annual seasonal influenza vaccination program is essential in health care settings. In order to promote annual seasonal influenza vaccination among health care worker, multipronged approach is recommended. Targeted educational intervention can be used to overcome the perceptual barriers on misconception about influenza and influenza vaccines. The organizational barriers can be fixed by introducing mobile vaccination team which provide services in flexible period of time around the workplace.