Spatiotemporal distribution of SARS-CoV-2 vaccines and vaccine-related proteins in mice and humans

Abstract Since the emergence of the COVID-19 pandemic, the successful distribution and application of mRNA vaccines have helped to contain the spread of SARS-CoV-2 and saved countless lives worldwide. mRNA vaccines are not only being developed and tested for infectious diseases, but also for numerous new applications, such as cancer therapy. Although the general mechanisms of mRNA vaccinations have been thoroughly studied, data regarding the local anatomical distribution after vaccination have been scarce. Here, we investigated the spatiotemporal distribution of BNT162b2 and mRNA-1273 vaccines in mice and deceased humans. We found that vaccine-related mRNA and spike protein could be detected at the vaccination site of patients and mice, with muscle-associated fibroblasts being a major source of spike protein expression. In contrast, we did not detect expression of vaccine-related spike protein in immune cells at the injection site. While mRNA-vaccine-related mRNA or spike protein could not be detected in extramuscular organs in humans in our study, it was detected in several organs in mice, even up to 7 days after initial vaccination. Together, these data enhance our understanding of mRNA vaccine kinetics and distribution patterns, providing valuable insights to guide scientists in refining future mRNA vaccine-based therapies whenever appropriate.