Figure 5 |. Spectrum and frequency of RNA variants in the Pfizer-BioNTech COVID-19 mRNA vaccine.
Total ARC-seq was applied to SARS-CoV-2 Spike mRNA purified from the Pfizer-BioNTech COVID-19 vaccine to assess the fidelity of T7 RNA polymerase in vaccine production. a, The variant frequency for vaccine mRNA is 2.24 x 10−4 (n=2). Samples come from separate vials (labeled Pfizer “A” and “B”) of the same lot. G>A transition was the dominant event subtype in vaccine samples (b) and most variants were nonsynonymous (c). Overall, the type of variants observed in Spike differs between vaccine and viral samples. d, e, Positional frequencies are less variable and fewer hot spots are observed in the vaccine (VAF = variant allele fraction). f, Compared to T7 IVT transcripts, vaccine mRNA has significantly more variants, and high GC content was associated with fewer polymerase errors in vitro. Analysis as in Figure 2.