Exemptions From Mandatory Immunization After Legally Mandated Parental Counseling

"The success of counseling-based interventions to address vaccine hesitancy is not clear. Evaluating the impact of a counseling intervention can provide important insight into population-level interventions that focus on interpersonal communication..."

This study evaluates the impact of adding parental counseling to requirements for obtaining vaccine exemptions in the United States (US), where state laws mandate that the parent of every child entering kindergarten either provide proof of immunisation or file for an exemption. Several states require health care provider counseling and/or signature to obtain a nonmedical exemption in an effort to ensure that parents have sufficient information about the risks of nonvaccination and to correct misperceptions about vaccine safety. However, evidence is mixed as to the success of such counseling-based interventions.

In the state of Washington, Senate Bill 5005 (SB5005) requires parents seeking an exemption to submit a Certificate of Exemption (COE) signed by a Washington-licensed health care provider documenting that the parent(s) have discussed "the benefits and risks of immunizations" with the provider. In order to evaluate the impact of adding a health care provider counseling and/or signature requirement to the Washington exemption process on subsequent vaccination and vaccine exemption rates, and on the local clustering of vaccine exemptions, the researchers studied coverage and exemption rates before and after the law, which was implemented in 2011, during Washington's school years 1997-1998 through 2013-2014.

Along with the relative decrease of 40.2% in exemption rates (95% confidence interval (CI), -43.6% to -36.6%), the researchers found a significant absolute reduction of 2.9 percentage points (95% CI, -4.2% to -1.7%) in immunisation exemption rates at the state level. The investigators also found an increase in vaccine coverage for all vaccines that are required to enter school (diphtheria-tetanus-pertussis, polio, pertussis, measles-mumps-rubella, hepatitis B, and varicella vaccines), except the hepatitis B vaccine. In addition, the law was linked to a decrease in geographic clusters of people with exemptions.

The researchers found no potential backfire effect from the counseling sessions - meaning that they were not linked to an increase in exemptions or decrease in vaccinations. Among the explanations: The clinical interaction between a health care provider and a parent revolves around not only correcting misinformation but also, among other things, increasing disease salience, which may be more relevant to parents. Moreover, research has found that physicians are the most trusted source of vaccine information in the US. Furthermore, the effect of this policy change might be caused by an increase in administrative difficulty of obtaining an exemption, rather than by persuasive interpersonal communications.

"The impact of adding parental counseling may depend on state-specific variation in immunization laws, health infrastructure, and other context-specific factors. Therefore, this type of analysis will have to be repeated for other states with recent changes in vaccine laws as their postchange data become available."