Background: Data on influenza vaccination coverage is typically measured and reported in terms of the proportion of eligible individuals vaccinated during a given influenza season. However, little is known about the regularity of vaccination uptake over multiple seasons.
Objectives: To measure the regularity of ongoing annual influenza vaccination among adults who were and were not vaccinated during the 2009-2010 vaccination season.
Methods: In 2010, we fielded an online survey to U.S. adults (n=4040). Respondents were asked whether they were vaccinated for seasonal influenza during the 2009-2010 season and whether they always, usually, or sometimes received the seasonal influenza vaccine in prior seasons. Results were weighted to be nationally representative. We generated descriptive statistics on ongoing vaccination behaviors.
Results: 30% of adults reported that they never receive influenza vaccinations. 27% reported “sometimes”, 10% reported “usually”, and 33% reported “always” being vaccinated for influenza. As expected, the regularity of vaccination differed (p<.01) depending on vaccination during the 2009-2010 season. Among those who reported being vaccinated in 2009-2010, 66% reported always being vaccinated, 10% reported usually being vaccinated, and 24% reported sometimes being vaccinated. By contrast, among those who were not vaccinated in 2009-2010, 10% reported always being vaccinated, 23% reported usually being vaccinated, and 67% reported sometimes being vaccinated.
Conclusions: We found considerable variation in the self-reported regularity of annual seasonal vaccination among subgroups of adults that was not well captured by simple questions about vaccination during the most recent flu season. These results suggest that information about vaccination histories could assist in the design and targeting of interventions to promote vaccinations.