A 9-year-old boy presents with sore throat and fever for 2 days. He has no cough or rhinorrhoea. Examination shows temperature 38.5 °C, tender anterior cervical lymphadenopathy and tonsillar exudates. A rapid antigen test confirms group A streptococcal pharyngitis. He has no history of rheumatic fever and lives in metropolitan Melbourne. What is the most appropriate management?