Antibiotics for the uncomplicated acute sore throat to prevent invasive group A Streptococcus - a critical analysis of current evidence

OBJECTIVE: Group A Streptococcus (GAS) can cause mild and severe infections. The most feared infection is invasive GAS (iGAS) infection. The objective of this study was to estimate to what extent the population incidence of iGAS infections can be reduced by providing antibiotic treatment to patients with an uncomplicated acute sore throat. METHODS: Compilation of existing relevant evidence linking antibiotic treatment of patients with an uncomplicated acute sore throat to the population prevalence of iGAS were identified. This information was combined with epidemiologic data from 2024 for the entire Swedish population. The primary outcome measure was the proportion of iGAS preventable by prescribing antibiotics to patients with uncomplicated acute sore throat. Secondary outcomes were the number of patients who need to have their throat swabbed and be prescribed antibiotics to prevent one case of iGAS. The outcome was stratified in different strategies, based on the Centor score, a commonly used clinical scoring algorithm for patients with an uncomplicated acute sore throat. RESULTS: Up to 6.7% of iGAS cases in children and ≤2.8% in adults can be prevented, assuming all patients with an uncomplicated acute sore throat attending a health care provider have a throat swab and those harboring GAS are prescribed antibiotics. Swabbing only patients fulfilling 3-4 Centor criteria and prescribing antibiotics if GAS is present would prevent ≤1.6% of iGAS cases in children and ≤1.2% in adults. The number needed to treat (NNT) for preventing one case of iGAS was for throat swabbing 45,000-110,000 and for antibiotic prescribing 12,000-110,000. CONCLUSIONS: A few iGAS infections are preventable by prescribing antibiotics to patients with an uncomplicated acute sore throat but this achievement is associated with large unintended consequences, such as side effects and a substantially increased workload for primary care. We propose that prevention of iGAS should not be a reason for prescribing antibiotics to patients with an uncomplicated acute sore throat.