Novel Thermostabilizing Formulation for Enhanced Stability of Foot-and-Mouth Disease Virus During Storage and Environmental Stress

Among the seven-foot-and-mouth disease virus (FMDV) serotypes, serotype O is relatively thermolabile, posing significant challenges for virus preservation and vaccine manufacturing. Therefore, this study aimed to develop an effective thermostabilizing formulation to enhance the thermal stability of thermolabile FMDV serotype O strains, thereby facilitating their long-term storage. The stabilizing effect of a newly developed stabilizer, designated CVS, was assessed using two Korean field isolates (O/SKR/Jincheon/2014 and O/SKR/Boeun/2017) and two recombinant strains [O1 Manisa (R) and O PanAsia-2 (R)]. CVS was compared with conventional stabilizers consisting of 3% sucrose and 10% glycerol. Viral seed stocks were stored at −80 °C, 4 °C, 25 °C and 37 °C for 2, 4, and 7 d or subjected to accelerated stress conditions, after which viral thermostability was comparatively evaluated. Although 3% sucrose provided moderate protection, the CVS formulation demonstrated significantly superior stabilizing efficacy on viral infectivity, particularly under high-temperature stress conditions (25 °C and 37 °C) and during freeze–thaw cycles. However, the stabilizing effect varied among strains, suggesting strain-dependent differences in physicochemical properties and structural stability. Overall, CVS improved FMDV infectivity stability across a broad temperature range and exhibited greater protective efficacy than 3% sucrose, supporting its potential as an effective FMDV stabilizer.