State laws and racial disparity in healthcare worker influenza vaccination rates

Modest healthcare worker (HCW) influenza vaccination rates across the US have spawned considerable research into methods to increase rates. Less commonly studied has been the role of law in this area. Of particular interest is the relationship between state laws regulating HCW influenza vaccination and HCW vaccination rates. To date, little empirical evidence exists to demonstrate these relationships. We used National Health Interview Survey (NHIS) data which include various immunizations and demographic characteristics such as sex, race, and occupation. Multiple years of data (2006-2010) were combined to produce reliable state-level estimates. The presence or absence of state laws regulating HCW influenza immunization was based on a summary conducted by the Centers for Disease Control and Prevention. Because HCW are clustered within states, two-level hierarchical linear modeling (HLM) was used to determine the effect of state HCW influenza vaccination laws on HCW influenza vaccination status (outcome variable). Race (white vs. nonwhite) was used as the level-1 variable and found to be associated with HCW influenza vaccination status (p<0.002), confirming racial disparities in influenza vaccination rates observed in the general population. When the presence or absence of state law was used as the level-2 variable (p<0.0001), differences across groups were observed. That is, in states where state laws regulate HCW influenza vaccination, there were smaller differences between white and non-white HCW influenza vaccination rates; whereas, in states without such laws, larger racial disparities persisted.