Fractionation of mRNA vaccines improves immune responses 

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Presentation Time: 08:45 AM - 09:00 AM
Abstract ID: 6096 - B

Presenting Author:
Sarah Sanchez , PhD Candidate at Northwestern Univ. Feinberg Sch. of Med.

Abstract:

 

mRNA vaccines are used to prevent SARS-CoV-2 infection and are being explored for other infectious diseases as well as cancer. While they have shown high efficacy at preventing COVID-19, waning immunity has motivated the development of improved mRNA vaccine formulations. Vaccine fractionation has been explored previously in the context of viral vector and protein immunogens, but its effect on mRNA vaccines is still unclear. We interrogated whether fractionating an mRNA-SARS-CoV-2 spike vaccine over three days, as opposed to a single dose, would enhance immune responses in C57BL/6 mice. We compared the immune responses induced by three consecutive 1 μg doses over three days (fractionated vaccine) with a single 3 μg dose. Despite the equivalent overall dosage, the fractionated vaccine demonstrated superior CD8 T cell responses. This pattern of enhanced immune responses with the fractionated vaccine regimen was also observed with an mRNA-HIV vaccine, suggesting generalizability. Taken together, these findings suggest that prolonging the duration of antigen expression through mRNA vaccination could enhance immune responses, supporting the rationale for developing slow-release formulations for mRNA vaccines.