It is my understanding that they used the pseudouridine because it:
“It is demonstrated that Ψ can enhance RNA stability and, in the meantime, decrease anti-RNA immune response (Karikó et al., 2008)”
Beyond this, are there studies that show the safety of using pseudouridine long them. I didn’t see any.
The Critical Contribution of Pseudouridine to mRNA COVID-19 Vaccines
frontiersin.org/article…