Primary care physicians in the United Kingdom carry out more than 300 million patient consultations every year and at least a quarter of these deal with children. Almost two-thirds of such appointments are for coughs, sore throats, or earaches—illnesses that young children commonly get. Doctors and nurses group these types of illnesses as “acute respiratory tract infections.” They are considered to be “self-limiting,” meaning that antibiotics have little or no benefit and that the illness will go away in time. Yet, in at least 30 percent of these consultations, antibiotics are prescribed. That’s an estimated 13 million unnecessary antibiotic prescriptions. This is not only wasteful but may also have unintended consequences for the child’s health. Indeed, in our new study of more than 250,000 children in the UK, we found that preschool children who had taken two or more antibiotic courses for acute respiratory tract infections in the preceding year had around a 30 percent …