Vaccines that are mass used for now are Pfizer, and after it are Sputnik and Sinofarm. Country like UAE, who is ranking high in vaccination, is using Sputnik and Sinofarm. They are rich, they do beleive in these vaccines so do I.
UAE is currently using four different vaccines - Pfizer-BioNTech, Oxford-AstraZeneca, Sputnik V and Sinopharm. Now these four have varying efficacy rates, ranging from 95% for the Pfizer vaccine to 62% for AstraZeneca. They received the vaccines in time not because they are rich. They received them on time, because they were one of the first countries to sign contracts with the vaccine manufacturers.