Neutralization titers correlated with spike-binding titers (Spearman r=0.87, p<0.0001). 50% of the low titer categories, 90% of the moderate, and 100% of the high had neutralizing activity. After comparing overall titers from the 30-day blood draw to the 82-day blood draw, the authors saw a geometric mean titer (GMT) decrease from 670 to 642. The high titer category experienced a drop in titer while individuals in low and medium category increased.