Fig. 4: mRNA booster vaccination protects against lower respiratory infection by SARS-CoV-2 Omicron in aged mice.
From: mRNA booster vaccination protects aged mice against the SARS-CoV-2 Omicron variant
SARS-CoV-2 mRNA BNT162b2-immunized 5-, 13-, and 21-month-old mice were challenged intranasally with 105 plaque-forming units (PFU) of SARS-CoV-2 Omicron at week 38 as indicated in Fig. 1. Viral titers (a) and gene expression profiles of Rsad2 and Ifit2 shown as relative expression compared to Rlp13a (b) in lung homogenates at 2 days post challenge are shown. Bars represent geometric means. Pie charts show the proportion of mice within each group that had detectable virus in the lungs. Data were analyzed by Mann-Whitney test or Kruskal–Wallis test corrected for multiple comparisons. *P < 0.05, **P < 0.01, ***P < 0.001. N = 7–9 per group, except for 21 M Distant vax (N = 6) and 21 M Booster (N = 5) groups. c Correlations between lung PFU at 2 days post challenge and anti-spike IgG titer, hACE2-RBD inhibition rate, and pseudovirus neutralizing titers against SARS-CoV-2 WT and Omicron at week 36 are shown. Circles represent individual mice, and colors indicate the immunization regimens. Dotted lines indicate assay limits of detection. Black and gray lines respectively indicate linear regression and 95% confidence interval. Correlations were assessed by two-sided Spearman rank-correlation tests.
