Vaccine hesitancy in Argentina: Validation of WHO scale for parents.

Background: The WHO SAGE Working Group on Vaccine Hesitancy developed the Vaccine Hesitancy Scale (VHS) to identify and compare hesitancy in different global settings. The objectives of the study were to describe and analyze vaccine hesitancy and to validate the VHS in a group of parents in Buenos Aires city, Argentina.

Methods: A cross-sectional survey was conducted in parents of 1-3 and 12-15 year-old children at three health centres in Buenos Aires City, between June 2018 and May 2019. Sociodemographic data were collected together with history of refusal and/or delay in children's vaccination (defined as hesitancy). The 10-item VHS using 5-point Likert-scale (higher scores indicating lower hesitancy) was administered and children's immunization record cards were verified. Link between hesitancy and socio-demographic variables, and hesitancy and vaccination status was analyzed for five specific vaccines. Cronbach's α was used to determine internal consistency reliability and factor analysis to confirm survey subdomains. Simple and multiple regression analysis was used to examine associations between VHS scores and hesitancy, and VHS scores and vaccination status.

Results: Six hundred parents were surveyed and 469 immunization cards verified; 11.5% (n = 69) parents were hesitant. High maternal educational level showed significant association with hesitancy (OR 2.66 95% CI: 1.20-5.9) in the adjusted model. Hesitancy was significantly associated with incomplete MMR vaccination in children (OR 4.43 95% CI: 1.08-8.20) and HPV vaccination in adolescents (OR 3.75 95% CI: 1.54-9.12). Cronbach's α was 0.66 and factor analysis identified three underlying constructs: "Benefits", "Harms" and "Confidence in healthcare system". High scores in VHS were associated with lack of hesitancy (OR 1.2 95% CI: 1.13-1.27) and complete vaccination status (OR 1.07 95% CI: 1.02-1.12).

Conclusions: Hesitancy was associated with high maternal educational level, and incomplete MMR and HPV immunization status in children and adolescents. VHS was a reliable and valid tool in this population.