The Disease Influenced Vaccine Acceptance Scale-Six (DIVAS-6): Validation of a Measure to Assess Disease-Related COVID-19 Vaccine Attitudes and Concerns.

Patients with underlying comorbidities are particularly vulnerable to poor outcomes from SARS-CoV-2 infection. Despite the context-specific nature of vaccine hesitancy, there are currently no scales that incorporate disease or treatment-related hesitancy factors. We developed a six-item scale assessing disease-related COVID-19 vaccine attitudes and concerns (The Disease Influenced COVID-19 Vaccine Acceptance Scale-Six: DIVAS-6). A survey incorporating the DIVAS-6 was completed by 4683 participants with severe and/or chronic illness (3560 cancer; 842 diabetes; 281 multiple sclerosis (MS)). The survey included the Oxford COVID-19 Vaccine Hesitancy Scale, the Oxford COVID-19 Vaccine Confidence and Complacency Scale, demographic, disease-related, and vaccination status questions. The six items loaded onto two factors (disease complacency and vaccine vulnerability) using exploratory factor analysis and exploratory structural equation modeling. The two factors were internally consistent. Measurement invariance analysis showed the two factors displayed psychometric equivalence across the patient groups. Each factor significantly correlated with the two Oxford COVID-19 Vaccine scales, showing convergent validity. The summary score showed acceptable ability to discriminate vaccination status across diseases, with the total sample providing good-to-excellent discriminative ability. The DIVAS-6 has two factors measuring COVID-19 vaccine attitudes and concerns relating to potential complications of SARS-CoV-2 infection due to underlying disease (disease complacency) and vaccine-related impact on disease progression and treatment (vaccine vulnerability). This is the first validated scale to measure disease-related COVID-19 vaccine concerns and has been validated in people with cancer, diabetes, and MS. It is quick to administer and should assist with guiding information delivery about COVID-19 vaccination in medically vulnerable populations.