Background
Current UK and US guidance recommends workplace or school exclusion for 12-24h from commencement of antibiotics for individuals with group A streptococcal (GAS) infection or carriage, to reduce potential infection risk, including to health and social care staff. However, evidence for antibiotic choice, dose and duration are limited. We reviewed the evidence to inform public health guidance.
Methods
We conducted a systematic review (PROSPERO CRD42021290364) and meta-analysis to estimate the pooled proportion of throat cultures positive for GAS after initiating antibiotics. We searched Ovid MEDLINE (1946-), EMBASE (1974-) and Cochrane Library databases. We included experimental and observational studies with ≥10 participants with culture-confirmed GAS pharyngitis, scarlet fever or with pharyngeal carriage. Two reviewers independently screened studies, extracted data, and assessed risk of bias.
Results
Of 5068 unique records identified, 43 were included: 37 (86%) randomised controlled trials, 3 (7%) non-randomised controlled trials, 3 (7%) before-and-after studies. Most (33, 77%) were from North America, or from Europe (6, 14%). The proportion of individuals who remained culture-positive at day 1, 2 and 3-9 was 6.9% (95% CI 2.7-16.8%), 5.4% (2.1-13.3%) and 2.6% (1.6-4.2%). For penicillins and cephalosporins, day 1 positivity was 6.5% (2.5-16.1%) and 1.6% (0.04 - 42.9%), respectively. After completion of antibiotics, 3.1% (1.0-9.5%) were culture-positive within 72h, 8.9% (6.8-11.6%) at 72h-10d, and 9.9% (7.8-12.7%) at ≥10d.
Conclusions
Our study provides evidence in support of 12-24h exclusion periods for GAS, but also highlights the need for further studies given the methodological limitations of published studies and imprecision of pooled estimates.