The vaccine was administered as des

The vaccine was administered as described previously (El Sahly et al., 2009).
Briefly, the lyophilized vaccine was reconstituted with 0.25 mL of sterile water for injection yielding a vaccine concentration of 1.6 × 109 CFU/mL.
The study design and administration of the vaccine were described in detail previously (El Sahly et al., 2009), with dosages of 103, 105, 107 and 109 CFU/mL administered by scarification with a bifurcated needle.
Five paired sera (pre- and 42 days post-vaccination) and three unpaired sera (post-vaccination) were provided.