Measuring State Vaccine Exemption Laws for Evaluation Research

Reports of vaccine-targeted disease outbreaks are increasing, along with the number of citizens who question the need for - and safety of - various vaccines, and their use of non-medical exemptions (NMEs). Against this background is a complex, interconnected network of state NME statutes, regulations and policies. Evaluation of NMEs can yield meaningful insights into how use of these exemptions affects public health. To ascertain the nature of variability in NMEs, relevant laws were collected longitudinally (2000-2007) and characterized using five general attributes and 25 specific attributes, including the populations and institutions subject to NME laws; application, review and appeal procedures; and potential for civil or criminal penalties. Two public health legal experts independently used a five-point Likert scale to rate NME laws for all 51 jurisdictions over eight years (408 observations) by level of “restrictiveness.” A third senior public health law expert adjudicated differences in ratings. Inter-rater reliability was high. For 2007, the distribution of state NME restrictiveness ratings was: 1 (very low) = 6 (11.8%), 2 = 11 (21.6%), 3 = 22 (43.1%), 4 = 10 (19.6%) and 5 (very high) = 2 (3.9%). This methodological approach should be generalizable to other areas of empirical public health law science. Future vaccine policy-relevant research could investigate state NME restrictiveness and specific attributes of NME laws as determinants of vaccine uptake rates, vaccine-targeted infectious disease incidence, and variation in parental, medical and school official vaccination-related attitudes, decisions and behaviors.