Crying non-stop for 3 hours or more after a vaccine can be scary. Fortunately, DTaP crying is not caused by encephalitis or any other terrible thing you might read about. It is a painful local reaction.
DTP vaccines protect our kids against diphtheria, tetanus, and pertussis and include DTaP, Tdap, and TD.
The current acellular pertussis vaccines include DTaP and Tdap.