There are many different concerns. I havent done a rigorous meta-analysis but they also come from very respectable scientists. > https://www.businessinsider.co

There are many different concerns. I havent done a rigorous meta-analysis but they also come from very respectable scientists. > https://www.businessinsider.com/coronavirus-vaccine-may-be-impossible-to-produce-scientists-covid-2020-4 https://www.businessinsider.com/coronavirus-vaccine-may-be-i... https://www.telegraph.co.uk/global-health/science-and-disease/funds-will-vaccine-coronavirus-really-possible/ https://www.telegraph.co.uk/global-health/science-and-diseas... And notice that there haven't been very exciting news from the vaccine developmnent trials. If anything there were more setbacks than pleasant surprises.