In the originally published version of this paper, an incorrect version of Figure 6 was included. Data from two immunization groups were missing from Figures 6E, 6F, 6H, 6I, and 6J. The corrected version includes the missing data and combines Figures 6I and 6J into a single panel, Figure 6I. The original version appears here, and the corrected version appears here and with the paper online.
The authors regret this error.