There have at least been studies that have found mRNA after 15 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9313234/ https://www.ncbi.nlm.nih.gov/pmc/articles/

There have at least been studies that have found mRNA after 15 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9313234/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9313234/) and 28 days (https://onlinelibrary.wiley.com/doi/10.1111/apm.13294 https://onlinelibrary.wiley.com/doi/10.1111/apm.13294) and other that show spike proteins months after vaccination. not restricted to the injection site: https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(23)00366-3/fulltext https://www.thelancet.com/journals/ebiom/article/PIIS2352-39...