Fig. 7: Efficacy of one or two doses of MPV/S-2P against SARS-CoV-2 challenge virus replication.

On days 31 or 32 post-prime [MPV- (gray) and MPV/S-2P-immunized macaques, blue] or on day 58 (corresponding to day 30 post-boost; MPV/S-2P-immunized macaques, gold) (n = 4 animals per group), macaques were challenged IN/IT with 6.3 log₁₀ TCID₅₀ of SARS-CoV-2, strain WA1/2020 (Fig. 1A). SARS-CoV-2 subgenomic E (sgE) RNA in the upper (A) and lower airways (B) following challenge. Nasopharyngeal swabs (NS) and bronchoalveolar lavages (BAL) were collected, and SARS-CoV-2 sgE mRNA, indicative of transcription/de-novo RNA synthesis and challenge virus replication, was quantified by RT-qPCR. C SARS-CoV-2 replication in lung tissues. On day 6 pc, SARS-CoV-2 sgE was quantified by RT-qPCR in six regions of lung tissues from each macaque. In each graph, the number of macaques with detectable sgE is indicated. Limit of detection: 2.85 log₁₀ copies/ml for NS and BAL; 3.6 log₁₀ copies/g for lung tissue. A–C Medians (lines), min and max values (whiskers), 25th to 75th quartiles (boxes), and individual values are shown two-way ANOVA with Sidak post-test; exact p values are indicated for levels of significance p < 0.05. Source data are provided in the Source Data file.