Lower viral loads in Group 20 and 40 SIVΔnef-vaccinated animals post-challenge.

(A) Excluding animals that were sterilely protected in Groups 20 and 40, SIVΔnef-vaccinated animals infected at weeks 20 and 40 displayed sustained virological control during the first 20 weeks of challenge compared to control animals. In contrast, Group 5 animals only transiently suppressed SIV replication during peak viremia. Statistical tests conducted were all two-tailed Mann-Whitney tests. (B) Linear mixed model of plasma viral load for each group including all animals, infected and uninfected with wild-type challenge virus. The linear mixed model compared the viral loads of each vaccination group to the control group at three phases during the course of viral infection (shaded in grey): peak viremia, viral set-point (weeks 5 to 12), and chronic infection (weeks 13 to 22). Group 20 and 40 animals again demonstrate sustained virological suppression during the first 20 weeks post-challenge.