BALB/c mice (N = 5–6) were immunized twice with 10 μg mRNA/LNP vaccine or DS-Cav1 protein formulated with Adju-Phos®. Sera taken 2 weeks following the second immunization was assayed for the presence of D25-competing antibodies (DCA, (gray bar), palivizumab-competing antibodies (PCA, (striped bar), or 4D7 competing antibodies (4D7 CA, (white bar)). The geometric mean antibody titer needed to inhibit 50% of mAb (D25, palivizumab, or 4D7) binding to RSV F protein (IT50) is shown, along with the 95% confidence interval (CI). The dotted line indicates the limit of detection of the competition ELISA. DCA, PCA and 4D7 competing titers were compared within each group by one-way ANOVA using Graph Pad Prism software. Differences between titers within each immunization group are shown (p < 0.05 = *, p < 0.01 = **).