Viruses can alter DNA, which is why they are being researched and used to treat some diseases, to fix flawed genes: https://www.sciencenews.org/article/gene-therapy-virus-crispr-editing-disease . My celiac was triggered by catching H1N1 14 years ago; the virus didn't alter my DNA, it just activated my existing HLA-DQ8 haplotype. Vaccines, including mRNA, are designed to alert our immune systems that an alien bacteria/virus is invading our systems. They don't alter DNA because they contain chemical pieces rather than DNA. ResearchGate is a good source for medical and other scientific research. Most of the "science" that is posted online is not peer-reviewed research, it is unsupported opinion. I post this as a scientist. Genetic and mRNA research is new (at least to me, being 70), so there is a lot to learn, and lots of unknowns. https://hcrl.wustl.edu/claims-that-mrna-vaccines-change-human-dna-are-back/ . https://www.health.gov.au/our-work/covid-19-vaccines/is-it-true/is-it-true-can-covid-19-vaccines-alter-my-dna