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Understanding and preventing off-target effects of therapeutic mRNAs


Since the successful development of mRNA vaccines for COVID-19, this technology is now considered game changing for the future development of vaccines as well as in therapeutics for cancer, cardiovascular disease and immunological diseases.

As part of on-going work to ensure this new technology is as safe and effective as possible, researchers at the MRC Toxicology Unit at the University of Cambridge have studied the mechanisms of the Pfizer–BioNTech BNT162b2 mRNA vaccine in detail.

They report that the majority of proteins are made as intended, but there are also some off-target immune responses due to a chemical modification made in the sequence of the mRNA. While there are no adverse outcomes in relation the safety of the COVID-19 mRNA vaccines as a result of this finding, it’s important that those looking to use this technology in future recognise this could have an impact when developing new drugs. The team have also already found a solution to this unintended response, which could be easily implement when designing future therapeutics. The research will be published in Nature.

Journalists came to this SMC briefing to hear two of the authors speak about their work.


Speakers included:

Prof Anne Willis, Director of the MRC Toxicology Unit, University of Cambridge.

Dr James Thaventhiran, MRC Investigator, MRC Toxicology Unit, University of Cambridge


This briefing was accompanied by an SMC Roundup of Comments.

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