To find the measure of side E'F' after rectangle EFGH is dilated by a scale factor of 33, we can use the following relationship:
\[ \text{New side length} = \text{Original side length} \times \text{Scale factor} \]
Given that side EF measures 22 and the scale factor is 33, we can calculate the new side length E'F' as follows:
\[ E'F' = EF \times \text{Scale factor} = 22 \times 33 \]
Calculating this:
\[ E'F' = 22 \times 33 = 726 \]
Therefore, the measure of side E'F' is \( \boxed{726} \).