Dirty mice better recapitulate key features of mRNA vaccine immunogenicity observed in humans

The development of mRNA vaccines during the COVID-19 pandemic dramatically reduced hospitalization and death rates for infected individuals. However, booster vaccinations were required to achieve full efficacy, and protection waned over time. Our research leveraged a "dirty" mouse model to test whether SARS-CoV-2 mRNA vaccinations in animals with previous microbial exposure better modelled human immune responses. We found that dirty mice require a booster vaccination for full efficacy and experienced waning serum antibody titer over time. We propose this approach as a future model for robust preclinical mRNA vaccine testing.