Measuring vaccine hesitancy: Field testing the WHO SAGE Working Group on Vaccine Hesitancy survey tool in Guatemala.

Background: Despite safe and effective childhood immunizations, decreased acceptance of vaccines has become an emerging global problem. The WHO SAGE Working Group on Vaccine Hesitancy developed a common diagnostic tool, the Vaccine Hesitancy Scale (VHS), to identify and compare hesitancy in different global settings. We field tested the VHS in rural and urban Guatemala.

Methods: We analyzed data from the enrollment visit of a study conducted at four public health clinics in Guatemala. Infants ages 6 weeks-6 months presenting for their first wellness visit were enrolled March-November 2016. Parents completed a demographic survey that included the 10 dichotomous and 10 Likert scale VHS questions. Chi-square or Fisher's exact for categorical and ANOVA test for continuous variables were used to assess significance levels in survey differences. We conducted a factor analysis to assess the Likert scale questions.

Results: Of 1088 families screened, 871 were eligible and 720 (82.7%) participated. No parent had ever refused a vaccination, and only eight parents (1.1%) had been reluctant or hesitated to get a vaccination for their children. However, only 40.8% (n = 294) of parents said that they think most parents like them have their children vaccinated with all the recommended vaccines. Factor analysis identified two underlying constructs that had eigenvalues of 1.0 or greater and a substantive lack of variability in response across the Likert scale. There were consistent differences between how study clinics responded to the ordinal scaling.

Conclusion: Our results suggest problems with interpretation of the VHS, especially in the presence of vaccine shortages and using a Likert scale that does not resonate across diverse cultural settings. Our factor analysis suggests that the Likert scale items are more one-dimensional and do not represent the multiple constructs of vaccine hesitancy. We suggest more work is needed to refine this survey for improved reliability and validity. Clinical Trial Registry: NCT02567006.