A paper published December 6 on Nature reveals a new finding about the BNT162b2 vaccine, which is an mRNA vaccine against COVID-19 known as Comirnaty®, produced by BioNTech, and marketed by Pfizer. The vaccine contains a modified nucleotide called N1-methylpseudouridine (m1Ψ), which is supposed to improve the vaccine’s performance and safety. However, the paper shows that m1Ψ also causes a phenomenon called +1 ribosomal frameshifting, which means that the ribosome, the cellular machine that reads the mRNA and makes proteins, skips one nucleotide and reads the wrong code. This results in the production of abnormal proteins that are different from the intended ones.
The paper suggests that these abnormal proteins, called +1 frameshifted products, can trigger an immune response in the vaccinated individuals, both in mice and humans. This means that the immune system recognizes them as foreign and tries to eliminate them. The paper does not provide any evidence that this immune response is harmful or beneficial, but it raises some questions about the potential consequences of this phenomenon.
Some possible negative effects of +1 ribosomal frameshifting and the resulting immune response are:
- Reduced vaccine efficacy: If the immune system is busy fighting the +1 frameshifted products, it may not be able to mount a strong enough response against the actual virus or its variants. This could lower the protection that the vaccine provides against COVID-19 infection and disease.
- Autoimmune reactions: If the +1 frameshifted products resemble some of the body’s own proteins, the immune system may mistakenly attack them and cause inflammation and damage to healthy tissues. This could lead to autoimmune diseases or worsen existing ones.
- Allergic reactions: If the +1 frameshifted products are highly allergenic, they may cause severe allergic reactions in some individuals, such as anaphylaxis, which can be life-threatening. This could limit the safety and acceptability of the vaccine.
More research is needed to understand the frequency, magnitude, and implications of +1 ribosomal frameshifting and the immune response to the +1 frameshifted products in the BNT162b2 vaccine. However, the paper estimates that the +1 frameshifted products account for about 8% of the total protein produced from the vaccine mRNA. This is a considerable proportion of the total protein, and it may have a significant impact on the vaccine’s safety or efficacy.
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