Objectives: We sought to evaluate longitudinal trends in people's risk perceptions and vaccination intentions during the 2009 H1N1 pandemic.
Methods: We used data from 10 waves of a US national survey focusing on the H1N1 pandemic (administered between May 2009 and January 2010) to conduct a longitudinal analysis of adult respondents' risk perceptions and vaccination intentions.
Results: Self-reported perceived risk of becoming infected with H1N1 paralleled H1N1 activity throughout the pandemic's first year. However, intention to be vaccinated declined from 50% (May 2009) to 16% (January 2010) among those who remained unvaccinated (27% had been vaccinated by January 2010). Respondents who indicated that they had previously been vaccinated against seasonal influenza reported significantly higher H1N1 vaccination intentions than those who had not been vaccinated (67% vs 26%; P < .001).
Conclusions: Reported intention to be vaccinated declined well before vaccine became available and decreased throughout the pandemic year. To the extent that prior vaccination for seasonal influenza vaccination is a strong correlate of H1N1 risk perceptions, encouraging seasonal influenza vaccination may benefit pandemic preparedness efforts.