Above all, do no harm

New parents arrive in your office with their infant son. They have brought a magazine article describing a case of serious neurologic injury sustained by a little girl apparently as a result of routine vaccination. The parent s are concerned that their son is at risk for a severe reaction to the DTP [diphtheria-tetanus-pertussis] vaccine. Although you believe that the benef its of vaccination generally outweigh the risks, you decide to review the c urrent evidence. Using the National Library of Medicine's PubMed site on th e Internet, you search using the terms pertussis, vaccination, and adverse effects, finding several randomized controlled trials (RCTs), cohort and ca se-control studies, and many review articles. You select acid retrieve 2 RC Ts, 2 large cohort studies, and 2 case-control studies that appear to addre ss your question.