Invasive Group A Strep Infections in Children Surge 40%: CDC Issues Clinical Alert
Quick Facts
Why Are Invasive Group A Strep Infections Rising in Children?
CDC Active Bacterial Core surveillance (ABCs) has documented a substantial increase in invasive Group A Streptococcus cases in children compared to pre-pandemic baselines. The CDC first issued a Health Alert Network advisory (HAN-00484) in December 2022 warning of rising iGAS in children, and surveillance data from subsequent seasons has continued to show elevated case counts. Young children, particularly those aged 1–4, have been disproportionately affected. Clinicians are urged to maintain a high index of suspicion for iGAS in children presenting with rapidly progressive soft tissue infections, persistent high fever after viral illness, or signs of sepsis.
Genomic surveillance has revealed that the M1UK lineage—a hypervirulent clone first identified in the United Kingdom—has become increasingly prevalent among invasive isolates in the US and globally. This lineage produces elevated levels of streptococcal pyrogenic exotoxin A (SpeA), which acts as a superantigen and can trigger toxic shock syndrome. Concurrent influenza A and RSV infections appear to facilitate GAS invasion by damaging respiratory epithelium and impairing mucosal immunity, creating a pathway for bacterial translocation. The World Health Organization also issued a disease outbreak notice in December 2022 noting increases in iGAS across multiple countries.
What Are the Warning Signs Parents Should Watch For?
While most Group A Strep infections cause mild pharyngitis or impetigo, invasive disease can escalate within hours. Key red flags include: persistent fever above 39.5°C (103°F) for more than 48 hours despite appropriate antibiotics, rapidly expanding erythema or skin discoloration with disproportionate pain, tachycardia, hypotension, decreased urine output, and altered mental status. Necrotizing fasciitis may initially mimic cellulitis but is distinguished by pain out of proportion to visible findings, crepitus, and systemic toxicity.
Streptococcal toxic shock syndrome (STSS) carries a mortality rate of approximately 25–35% even with aggressive treatment and can develop secondary to pharyngitis, varicella skin lesions, or minor wounds. Current guidelines recommend that emergency departments perform blood cultures and begin empiric intravenous penicillin plus clindamycin in any child with suspected invasive GAS, as clindamycin inhibits toxin production independent of bacterial replication. Intravenous immunoglobulin (IVIG) should be considered for confirmed STSS cases.
Frequently Asked Questions
Group A Streptococcus remains universally susceptible to penicillin and amoxicillin, which are the first-line treatments. However, macrolide resistance (erythromycin, azithromycin) has been reported in a notable proportion of US isolates. The addition of clindamycin in invasive cases is recommended not for resistance concerns but because it directly suppresses toxin production even when bacteria are not actively dividing.
No vaccine is currently approved for Group A Streptococcus, though several candidates are in clinical development. Research groups including those at the University of Queensland and other institutions are pursuing M-protein-based and other vaccine strategies. Given the complexity of GAS with over 200 known emm types, developing a broadly protective vaccine has been challenging, but progress in recent years has been encouraging.
Yes. Children with confirmed strep throat should remain home until they have been on appropriate antibiotics for at least 12–24 hours and are fever-free. Completing the full 10-day course of penicillin or amoxicillin is essential to prevent rheumatic fever and reduce transmission to classmates and family members.
References
- Centers for Disease Control and Prevention. Health Alert Network Health Advisory: Increase in Invasive Group A Streptococcal (iGAS) Infections Among Children. HAN-00484. December 22, 2022.
- World Health Organization. Disease Outbreak News: Increased incidence of scarlet fever and invasive Group A Streptococcus infection — multi-country. December 15, 2022.
- Lynskey NN et al. Emergence of dominant toxigenic M1T1 Streptococcus pyogenes clone during increased scarlet fever activity in England: a population-based molecular epidemiological study. The Lancet Infectious Diseases. 2019;19(11):1209–1218.
- Stevens DL et al. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. Clinical Infectious Diseases. 2014;59(2):e10–e52.