Extreme Allergic Reaction Question.

Well, when I was 2-3 I had my DPT booster shot. I had a severe allergic reaction to the D(Diphtheria) and the P(Pertussis [Whooping Cough]) portion of it and my temperature shot up rapidly and I went into an coma for a few weeks. The neurologist and doctors apparently told my parents apparently that the reaction was so severe I wasn't expected to live past the age of 8. I recently retouched on this and would like to know if there is any ways that I could be re-exposed to Diphtheria and Pertussis and what precautions I should take to avoid them?