Table 6.

History of Homologous-type Detection and Antibiotic Receipt at Group A Streptococcus–Positive Visits With Typical Symptoms, Atypical Symptoms, and No Symptoms

Outcome	Previously Detected FIGE Type			Distinct FIGE Type Belonging to Previously Detected emm Type			Heterologous emm Type Belonging to Previously Detected emm Cluster
	No Previous Detectiona	Previous Detection		No Previous Detectiona	Previous Detection		No Previous Detectiona	Previous Detection
		No Antibiotic Prescribed	Antibiotic Prescribed		No Antibiotic Prescribed	Antibiotic Prescribed		No Antibiotic Prescribed	Antibiotic Prescribed
GAS-positive without symptoms, No. of visits	93	39	29	503	125	67	503	45	24
GAS-positive typical symptoms, No. of visits	112	6	12	150	6	9	150	2	5
GAS-positive atypical symptoms, No. of visits	28	3	9	42	6	9	42	3	4
Est. protection against typical symptoms, from any previous detection, % (95% CI)	Ref	89.6 (66.3–97.1)	71.2 (37.8–89.4)	Ref	95.1 (77.3–99.1)	94.1 (71.0–98.9)	Ref	86.7 (38.0–97.0)	48.8 (−75.4 to 88.4)
Est. protection against atypical symptoms, from any previous detection, % (95% CI)	Ref	42.0 (−168.8 to 87.0)	−51.9 (−363.0 to 56.6)	Ref	71.1 (−120.0 to 95.7)	−20.6 (−1705.0 to 86.1)	Ref	−25.8 (−379.1 to 64.0)	…

Estimates of protection are obtained as 1 minus the matched odds ratio, accounting for matching strata. We derive 95% CIs via cluster-bootstrap resampling of children. FIGE types are defined by matched banding patterns.

Abbreviations: CI, confidence interval; Est., estimated; FIGE, field inversion gel electrophoresis; GAS, group A Streptococcus; Ref, reference group.

^aWe define “no previous detection” as no prior detection of any isolate belonging to the same FIGE type, emm type, or emm cluster. Fewer observations are available for analyses of prior detection of the same FIGE type because we exclude second detections not separated from prior detections by ≥ 2 GAS-negative swabs.