Syringe injecting childThere has been speculation that the increase in the number of asthma cases over the last two decades may have something to do with the pertussis (whooping cough) vaccine. A letter to the editor, appearing in the Journal of the American Medical Association (1994;272(8):592-593) referred to a study of 448 children who were breast fed for the first six months of life. The children were evaluated (mean age 7.87 years). A total of 30 were determined to have asthma. Of the 243 children who had received immunizations, 26 were diagnosed with asthma. Only four of the 203 children who had not received immunizations were diagnosed with asthma, meaning that the immunized group had a more than a five-fold risk of developing the disease. The authors believed that the culprit was the pertussis vaccine because there were only three cases of asthma in the 112 children who did not receive the pertussis vaccine, but received all of their other vaccines.