Epidemiology of Invasive Group A Streptococcal Infections in the United States, 2005-2012

Clin Infect Dis. 2016 Aug 15;63(4):478-86. doi: 10.1093/cid/ciw248. Epub 2016 Apr 22.


Background: Invasive group A Streptococcus (GAS) infections are associated with significant morbidity and mortality rates. We report the epidemiology and trends of invasive GAS over 8 years of surveillance.

Methods: From January 2005 through December 2012, we collected data from the Centers for Disease Control and Prevention's Active Bacterial Core surveillance, a population-based network of 10 geographically diverse US sites (2012 population, 32.8 million). We defined invasive GAS as isolation of GAS from a normally sterile site or from a wound in a patient with necrotizing fasciitis (NF) or streptococcal toxic shock syndrome (STSS). Available isolates were emm typed. We calculated rates and made age- and race-adjusted national projections using census data.

Results: We identified 9557 cases (3.8 cases per 100 000 persons per year) with 1116 deaths (case-fatality rate, 11.7%). The case-fatality rates for septic shock, STSS, and NF were 45%, 38%, and 29%, respectively. The annual incidence was highest among persons aged ≥65 years (9.4/100 000) or <1 year (5.3) and among blacks (4.7/100 000). National rates remained steady over 8 years of surveillance. Factors independently associated with death included increasing age, residence in a nursing home, recent surgery, septic shock, NF, meningitis, isolated bacteremia, pneumonia, emm type 1 or 3, and underlying chronic illness or immunosuppression. An estimated 10 649-13 434 cases of invasive GAS infections occur in the United States annually, resulting in 1136-1607 deaths. In a 30-valent M-protein vaccine, emm types accounted for 91% of isolates.

Conclusions: The burden of invasive GAS infection in the United States remains substantial. Vaccines under development could have a considerable public health impact.

Keywords: epidemiology; group A Streptococcus; streptococcal toxic shock syndrome; surveillance; vaccine.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Bacteremia / epidemiology
  • Bacteremia / microbiology
  • Centers for Disease Control and Prevention, U.S.
  • Epidemiological Monitoring
  • Fasciitis, Necrotizing / epidemiology*
  • Fasciitis, Necrotizing / microbiology
  • Female
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Morbidity
  • Shock, Septic / epidemiology*
  • Shock, Septic / microbiology
  • Streptococcal Infections / epidemiology*
  • Streptococcal Infections / microbiology
  • Streptococcus pyogenes / classification*
  • Streptococcus pyogenes / isolation & purification
  • United States / epidemiology
  • Young Adult