DPT refers to a class of combination vaccines against three infectious diseases in humans:diphtheria, pertussis (whooping cough), and tetanus. The vaccine components include diphtheria and tetanus toxoids and killed whole cells of the organism that causes pertussis (wP). DTP vaccine seem to have negative non-specific effects other than the beneficial effect against the targeted disease. The negative effects are seen as long as DTP vaccine is the most recent vaccine. BCG or measles vaccine given after DTP reverses the negative effects of DTP. The negative effects are seen mostly in females.