Simply they would have got better regardless of the treatment. The immune system has done its job, most viruses run their course and after five to seven days the crisis is over. We do not exactly know, but it seems that the effect on the immune system can be catastrophic for the future. When a broad spectrum antibiotic, in fact any antibiotic, is introduced into the body, some of these beneficial bacteria are wiped out. The familiar complaint of diarrhoea is a common example of this disturbance.
Vaginal thrush is another, and all too familiar side effect.
To restore this fine balance can take months. So not only do you see a patient with the original infection, but various other opportunist ones too. These are often worse and more distressing to the patient than say the original sore throat. That's quite an alarming list considering how may thousands of patients are prescribed antibiotics each day. The answer is in many ways.