ABSTRACT
Introduction Despite people with underlying comorbidities being particularly vulnerable to poor outcomes from SARS-CoV-2 infection, vaccine hesitancy remains problematic. There are no scales that measure disease or treatment-related vaccine concerns. Methods We developed a six-item scale assessing disease-related COVID-19 vaccine attitudes and concerns (The Disease Influenced COVID-19 Vaccine Acceptance Scale: 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). The survey included the Oxford COVID-19 Vaccine Hesitancy Scale, the Oxford COVID-19 Vaccine Confidence and Complacency Scale, demographic, diseaserelated and vaccination status questions. Results Six items were loaded onto two factors, disease complacency and disease-related vaccine vulnerability. Cronbach's alpha was 0.73 and 0.85 respectively. 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 good-to-excellent vaccination status discriminative ability (95% CI .77-.80). Conclusions This is the first validated scale measuring disease-related COVID-19 vaccine attitudes and concerns and should assist with guiding information delivery about COVID-19 vaccination in medically vulnerable populations.