Oscillating temperatures and potential handling and storage errors tested do not compromise mRNA vaccine efficacy.
mRNA vaccine, Rabipur and HDC were reconstituted in buffer and subsequently stored at +40°C for one week (A-C). In a second experiment, RABV-G mRNA was stored as a lyophilisate at 56°C for 8–9 hours per day and then at 4°C for 15–16 hours with a total of 20 cycles of oscillating temperatures (D-F). Vaccine or control injections were done on day 0 and 21. Induction of rabies virus neutralization titer was measured on day 35 after first immunization (A, D: dashed line indicates the WHO standard titer of 0.5 IU/ml). Mice were challenged with a 40fold MLD50 of rabies virus CVS-11 on day 47 (B-C) or day 51 (E-F) and survival (B, E) and body weight (C, F) was recorded. As groups in A-F were treated in parallel, the buffer control group in Fig 3D–3F is valid also for Fig 3A–3C. For antibody titers, the mean is indicated, for body weight kinetics the mean and standard deviation is shown (n = 6 to 8). Significance: ns = non-significant, **p<0.01, ***p < .001 to HDC or buffer control group in A and D, respectively, was calculated using the Mann Whitney test.
