My son had Valley Fever last year. He never had to take the meds, but took 3 months to get back to normal and is fine now. I reluctantly gave him the DTap shoot for whooping cough and wonder if that will lower his immune system which triggers the fungus in the lungs from Valley Fever. I gave him the shot in about a month ago and he now has a cough that seems to be like allergies, but not 100% sure.
The Tap shot should not lower his immunity or trigger the fungus. Presumably his immune system fought off the fungus a year ago since he did finally get better. It is more likely the cough is related to something like allergies. However, I certainly understand your concern, so I think it would be a good idea for him to see his doctor and have his lungs examined and perhaps a chest X-ray, just to be sure there is not something more serious going on. Its possible he has bronchitis or asthma, and the doctor could diagnose this and treat it appropriately as well. Hope this helps.