The Novel Platform of mRNA COVID-19 Vaccines and Myocarditis: Clues into the Potential Underlying Mechanism

[...]some early commercial batches of the Pfizer-BioNTech’s vaccine contained lower than expected levels of intact mRNA as shown by leaked EMA documents [6]. [...]as the span of vaccinations is increasing beyond adults to include children aged 6 months to 12 years and given the fact that the rare potential association with myocarditis is more frequent among male adolescents, we propose the following two-tiered strategy: 1) Medical care should be sought in the presence of symptoms compatible with myocarditis, such as chest pain, dyspnea and palpitations, after COVID-19 vaccination, according to CDC’s preliminary instructions; and 2) the purification of the mRNA from in vitro transcription contaminants and the mRNA-LNP product stability need to be improved and carefully monitored for each vaccine batch. A. Klein: research grant, scientific advisory board Kiniksa Pharmaceuticals, Ltd; scientific advisory board Swedish Orphan Biovitrum AB; scientific advisory board Pfizer, Inc. Vaccine Moderna (CX-024414) Pfizer-BioNTech (Tozinameran) Sex Female Male Not specified Total Female Male Not specified Total Age group Not specified 0 0 0 0 4 7 1 12 0–1 month 0 0 0 0 0 0 0 0 2 months − 2 years 0 0 0 0 0 0 0 0 3–11 years 0 0 0 0 0 0 0 0 12–17 years 0 1 0 1 0 16 0 16 18–64 years 13 48 0 61 57 166 3 226 65–85 years 2 3 0 5 18 12 0 30 > 85 years 0 0 0 0 0 0 0 0 Total 15 52 0 67 79 201 4 284 Number of individual cases Reporter group Healthcare professional 62 211 Non-healthcare professional 5 73 Outcome Fatal 0 8 Not recovered/Not resolved 19 70 Recovered/Resolved 16 29 Recovered/Resolved with sequelae 0 7 Recovering/Resolving 12 58 Unknown 20 112 Table 1 Description of acute myocarditis cases post mRNA COVID-19 vaccination by vaccine type.