Fig. 6: Protective efficacy of a single dose of circRNA vaccine.

a Immunization schedule for the challenge experiment in the prime-only group. The figure was created by the author using Adobe Illustrator 2020. b–d Antibody titers against the NA recombinant proteins from Mich15 (c), SL32 (d), and BCOL17 (e) were measured using ELISA. The data present results from five mice per group. Dashed lines indicate the lowest initial dilution. Statistical significance was determined using One-way ANOVA; *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; ns denotes not significant. e Mice (n = 5) in the prime-only group were challenged with 5 × LD50 of B/Colorado/06/2017 (Victoria) virus. Body weight and survival rate were monitored for 14 days. Body weight was shown as the mean of five mice ± SD.