2009 H1N1 vaccination in Minnesota: an evaluation by ZIP code.

According to Minnesota Immunization Information Connection (MIIC) data, 23% of Minnesotans were vaccinated against 2009 pandemic H1N1 influenza. We analyzed 2009 H1N1 vaccination data at the ZIP code level to learn more about who received the vaccine between 2009 and 2010. We found significant differences in H1N1 vaccination rates by percentage of residents living below the family poverty line, percentage of non-Caucasian residents in a ZIP code and median family income. When stratified by urban or rural location, median family income was significantly associated with vaccination rate only in urban settings; the percentage of non-Caucasians living in an area was significant only in rural settings. In both urban and rural settings, most H1N1 vaccinations were given in a private facility, although the proportion was much higher in urban ZIP codes (81.5%) than rural ZIP codes (53.2%, P < 0.0001). Further research is needed to find out why vaccination rates were associated with increasing median family income in urban areas and why in rural areas, people living in ZIP codes with a higher percentage of non-Caucasian residents were more likely to be vaccinated after controlling for poverty and median income.