FYI, the first mRNA corona virus trials began in march 2020. If this person is correct, it has been months since the trials began in mid-March. Why haven’t we began seeing this effect?
Study to Describe the Safety, Tolerability, Immunogenicity, and Efficacy of RNA Vaccine Candidates Against COVID-19 in Healthy Individuals
https://clinicaltrials.gov/ct2/show/NCT04368728