# Safety and Biocompatibility of a Spray-Dried Influenza Microparticle Vaccine in Mice

## TL;DR

This study shows that a new type of influenza vaccine made from microparticles is safe and well-tolerated in mice.

## Contribution

The study introduces and evaluates the safety of two novel polymeric particle-based influenza vaccines in mice.

## Key findings

- The vaccines caused limited inflammation and no tissue damage in mice.
- No adverse side effects were observed in mice receiving either intranasal or subcutaneous immunization.

## Abstract

Influenza virus is a persistent source of morbidity and moribundity, and effective disease control requires ever-evolving effective vaccines. In this work, we evaluate the safety and biocompatibility of two novel polymeric particle-based influenza vaccines. Mice were immunized either intranasally or subcutaneously with these two formulations and examined at 1 h, 1 day, and 14 days post-immunization for histopathology in liver, kidneys, and lungs and serum biomarker analysis. Mice that received an intranasal vaccination were also observed for pulmonary disruption via whole body plethysmography. Examination of tissues post-immunization found only limited inflammation, with no difference observed in plethysmography measurements and no serum biomarkers (e.g., AST, AlkPhos) indicating tissue damage. Collectively, these data support the conclusion that these polymeric particle-based influenza vaccine formulations were well tolerated by the animals and did not induce any adverse side effects.

Particle-based influenza vaccines were safety tolerated by mice and did not induce any adverse side effects.

The online version contains supplementary material available at 10.1007/s40883-025-00473-2.