Antibiotics are among the most prescribed medications for children, but a significant proportion of prescriptions are for viral illnesses against which antibiotics have no effect. Understanding when antibiotics are genuinely needed — and when the appropriate treatment is watchful waiting and symptom management — helps parents have more informed conversations with healthcare professionals and reduces pressure on both children and the healthcare system.
The issue is not that antibiotics are harmful when genuinely indicated, but that unnecessary prescriptions expose children to side effects without benefit, and contribute to the growing problem of antibiotic resistance.
Healthbooq supports parents with evidence-based guidance on common childhood illnesses, including when antibiotics are genuinely indicated and how to manage viral illnesses effectively at home.
Antibiotics: What They Do and Do Not Do
Antibiotics kill or inhibit bacteria. They have no effect whatsoever on viruses — the most common cause of childhood respiratory and gastrointestinal illness. Taking an antibiotic for a viral illness does not shorten the illness, does not prevent complications, and does not prevent the child from being contagious; it simply exposes them to potential side effects and contributes to resistance.
The most common illnesses in young children — colds, most sore throats, most coughs, bronchitis, most ear infections, and gastroenteritis — are caused by viruses in the great majority of cases. The natural course of these illnesses involves resolution within one to two weeks. Antibiotic treatment does not change this.
Common Childhood Illnesses: Antibiotic Decision-Making
Sore throat (pharyngitis and tonsillitis) is caused by viruses in approximately eighty per cent of cases. Group A Streptococcus (Strep throat) causes the remaining twenty per cent and does respond to antibiotics (penicillin V is the first-line treatment). Clinical tools — including the Centor and McIsaac criteria — help clinicians identify which children are more likely to have streptococcal rather than viral infection, but testing (a throat swab) is the most reliable way to distinguish them. Most GPs in the UK do not routinely prescribe antibiotics for sore throat without evidence of bacterial cause.
Ear infections (acute otitis media) are caused by viruses in around sixty per cent of cases. NICE guidance recommends watchful waiting for most children with ear infections, with a deferred antibiotic prescription if symptoms have not resolved after two to three days. Antibiotics reduce the duration of pain modestly in bacterial ear infections but most infections resolve without them; in children under two or with severe infection, earlier antibiotic treatment is more likely to be recommended.
Coughs and chest infections: the vast majority of acute coughs in children are caused by viral upper respiratory infections. Bacterial pneumonia may require antibiotics (see pneumonia article); most coughs do not. A cough that is productive, persistent (more than three weeks), associated with high fever, or associated with signs of lower respiratory tract infection warrants assessment — but this does not mean that assessment will result in antibiotic prescription.
Urinary tract infections in children do require antibiotic treatment, as do impetigo, confirmed Strep A throat infection, bacterial pneumonia, whooping cough (pertussis), and Lyme disease.
Side Effects and Risks of Unnecessary Antibiotics
Antibiotics disrupt the gut microbiome — the community of bacteria in the intestine that plays important roles in immunity, metabolism, and digestive function. Disruption of the infant gut microbiome by early antibiotic use has been associated in longitudinal studies with increased risks of obesity, asthma, and allergic disease, though causality is not fully established. Immediate side effects include diarrhoea (common with amoxicillin), skin rashes, nausea, and secondary thrush (Candida) infections.
Antibiotic resistance — the development of bacteria that are not killed by standard antibiotic doses — is one of the major public health challenges of the twenty-first century. Each unnecessary antibiotic prescription contributes to the selective pressure that drives resistance.
When Antibiotics Are Prescribed: Completing the Course
When a doctor does prescribe antibiotics, completing the full prescribed course — even if the child appears to have recovered before it is finished — is important. Stopping antibiotics early because the child feels better risks allowing the most antibiotic-resistant bacteria to survive and multiply. The course length is determined by evidence of what duration reliably clears the specific infection.
Key Takeaways
Antibiotics treat bacterial infections and have no effect on viral infections, which cause the majority of common childhood illnesses including colds, most sore throats, most ear infections, most chest infections, most coughs, and gastroenteritis. Unnecessary antibiotic use exposes children to side effects (diarrhoea, rash, thrush), disrupts the gut microbiome, and contributes to antibiotic resistance. When antibiotics are genuinely indicated, completing the full course as prescribed is important. Parents who understand the difference between bacterial and viral illness are less likely to expect or pressure for unnecessary antibiotic prescriptions.
