There’s never been an mRNA vaccine [which uses the genetic code rather than any part of the virus itself] before for humans. So, this Pfizer vaccine, for instance, would be absolutely brand new, made in a new way.” source : the guardian

In areas of DNA where RNA binds to one of the DNA threads in such a way that the complementary DNA thread becomes the sole thread-R loop structure.  The DNA stability will change if RNA is chemically modified by m6A.

vaccine pfizer covid-19-side-effects-new-rna
Modified RNA has a direct effect on DNA

In areas of DNA where RNA binds to one of the DNA threads in such a way that the complementary DNA thread becomes the sole thread (R-loop structures), the DNA stability will change if RNA is chemically modified by m6A.
“Several research groups are now working together to study what effect this can have on the DNA molecule. We already know that R-loop areas are associated with sequences of DNA containing active genes and that this can lead to chromosomal breakage and the loss of genetic information,” explains Klungland.  –  

phys.org 

“There’s been no safety data yet, it hasn’t been peer-reviewed, there is a lot of indemnity to it and the MHRA [Medicines and Healthcare products Regulatory Agency], who are going to be the ones that approve it or not, we have found out, well, one, they’re a government body so they are paid for by the government, and two they’ve received nearly £1m in funding from the Bill and Melinda Gates Foundation. They are not a robustly independent body.

Just over an hour after Boris Johnson finished  a press conference in which he sought to manage expectations  following the interim results for the vaccine – which must gain regulatory approval before it is rolled out – Louise Creffield from Save Our Rights UK, which has campaigned against lockdown, made a Facebook live response.