Factors associated with uptake of vaccination against pandemic influenza: a systematic review.

Background: In June 2009 a global influenza pandemic was declared by the World Health Organisation. A vaccination programme against H1N1 influenza was introduced in many countries from September 2009, but there was low uptake in both the general population and health professionals in many, though not all, countries.

Purpose: To examine the psychological and demographic factors associated with uptake of vaccination during the 2009 pandemic.

Method: A systematic literature review searching Web of Science and PubMed databases up to 24 January 2011.

Results: 37 articles met the study inclusion criteria. Using the framework of Protection Motivation Theory the review found that both the degree of threat experienced in the 2009 pandemic influenza outbreak and perceptions of vaccination as an effective coping strategy were associated with stronger intentions and higher uptake of vaccination. Appraisal of threat resulted from both believing oneself to be at risk from developing H1N1 influenza and concern and worry about the disease. Appraisal of coping resulted from concerns about the safety of the vaccine and its side effects. There was evidence of an influence of social pressure in that people who thought that others wanted them to be vaccinated were more likely to do so and people getting their information about vaccination from official health sources being more likely to be vaccinated than those relying on unofficial sources. There was also a strong influence of past behaviour, with those having been vaccinated in the past against seasonal influenza being more likely to be vaccinated against pandemic influenza. Demographic factors associated with higher intentions and uptake of vaccination were: older age, male gender, being from an ethnic minority and, for health professionals, being a doctor.

Discussion: Interventions designed to increase vaccination rates could be developed and implemented in advance of a pandemic. Strategies to improve uptake of vaccination include interventions which highlight the risk posed by pandemic influenza while simultaneously offering tactics to ameliorate this risk (e.g. vaccination). Perceived concerns about vaccination can be tackled by reducing the omission bias (a perception that harm caused by action is worse than harm caused by inaction). In addition, interventions to increase seasonal influenza vaccination in advance of a future pandemic may be an effective strategy.