Background: Promoting vaccination uptake during influenza pandemic remains challenging. Traditional epidemiological questionnaire-based surveys had identified significant factors that could determine people’s vaccination choice during a pandemic but how people made trade-off among these factors when making their vaccination decision is unclear. This study measured the relative effects of altering different factors (attributes) in determining vaccination preference and compared their relative importance across three hypothetical pandemics: 1918-like influenza pandemic, avian influenza A/H5N1-like influenza pandemic and the 2009 influenza A/H1N1-like pandemic.
Methods: A total of 200 Hong Kong adults from the general public completed a tablet-assisted discrete choice experiment (DCE) survey. Multinomial logit models were conducted to evaluate relative preference weights for seven pre-determined attributes (i.e. infection probability (IP), case-fatality ratio of influenza (CFR), vaccine safety, vaccine efficacy, vaccination cost, prevalence of vaccination uptake in the community and doctors’ advice for vaccination.
Results: In a mild pandemic (2009 influenza A/H1N1-like pandemic) of which IP and CFR are set to be 10% and 0.1%, respectively, influenza risk was less important than was vaccination risk, while community vaccination uptake rate played a dominant role followed by vaccine efficacy and doctors’ advice, in determining vaccination preference. In a 1918 influenza-like pandemic (IP: 20%, CFR: 10%), community vaccination uptake rate was the most important, followed by vaccine efficacy and doctors’ advice, in determining vaccination choice. In an A/H5N1-like pandemic (IP: 30% and CFR: 20%), influenza risk became the dominant influence on vaccination preference.
Conclusion: In a mild pandemic when population concern over vaccine risk is likely to be an important barrier for promoting vaccination uptake, doctors’ recommendation for vaccination and reporting the increasing vaccination statistics may be helpful to improve uptake. In a severe pandemic, information of disease risk becomes the most important determinant of those studied that promotes vaccination uptake.