Willingness, beliefs, and barriers regarding the COVID-19 vaccine in Saudi Arabia: a multiregional cross-sectional study oleh Noura Altulahi, Shouq AlNujaim, Azzam Alabdulqader, Abdullah Alkharashi, Assaf AlMalki, Faisal AlSiari, Yara Bashawri, Sarah Alsubaie, Dayel AlShahrani, Yara AlGoraini