State Policy Effectiveness Map (IMAGE) University of Georgia Caption "Most effective" states are those in the highest quartile of the exemption law effectiveness index; "least effective" states are those in the lowest quartile. Mississippi and West Virginia do not permit nonmedical exemptions from vaccination requirements. Credit <em>Health Affairs</em> Usage Restrictions The image may only be used with appropriate credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.