If the blood test looked for Pertussis antibodies, it is a very good test. If your children have wheezing and coughing triggered by the adenovirus and/or Mycoplasma, it is possible they will have their symptoms for several weeks. Sometimes Mycoplasma-induced wheezing lasts for much longer, particularly in children who have had wheezing before. The infection is gone in less time, but the inflammatory reaction in the lungs persists. This looks a lot like asthma, but usually clears up. If the symptoms in your children are either persisting or getting worse, I would keep in close contact with your allergist.