Some group A strep infections cause invasive disease. Invasive disease means that germs invade parts of the body that are normally free from germs.

CDC estimates approximately 11,000 to 24,000 cases of invasive group A strep disease occur each year in the United States. Each year between 1,200 and 1,900 people die due to invasive group A strep disease. Invasive group A strep disease can include:

  • Cellulitis with blood infection
  • Necrotizing fasciitis
  • Pneumonia
  • Streptococcal toxic shock syndrome

In contrast, experts estimate that several million cases of non-invasive group A strep illnesses occur each year. Non-invasive group A strep diseases include strep throat and impetigo. Complications of these group A strep infections, like post-streptococcal glomerulonephritis and acute rheumatic fever, are rare.

Globally, the burden from group A strep infections is even greater. For example, the World Health Organization estimates:

  • 111 million children in the developing world have impetigo1
  • 470,000 new cases of acute rheumatic fever occur each year1
  • 282,000 new cases of rheumatic heart disease occur each year1
  • 15.6 million persons have rheumatic heart disease1
Bact Facts Interactive
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Analyze and visualize ABCs group A strep data using Bact Facts Interactive.

Surveillance Systems

CDC does not track non-invasive group A strep infections.

CDC tracks invasive group A strep infections through Active Bacterial Core surveillance (ABCs), a population-based, active- and laboratory-based surveillance system. This means local and state health departments routinely contact laboratories to identify all cases, then report those cases to CDC.

Currently, the only nationally reported group A strep disease is streptococcal toxic shock syndrome. Healthcare providers and laboratories should report cases to the appropriate health department. States then report these cases to CDC through the National Notifiable Diseases Surveillance System (NNDSS).

Disease Trends

Group A strep infections can occur any time during the year. However, some infections are more common in the United States in certain seasons:

  • Strep throat and scarlet fever are more common in the winter and spring.
  • Impetigo is more common in the summer.

Anyone can get a group A strep infection, but some infections are more common in certain age groups:

  • Strep throat and scarlet fever are most common in children between the ages of 5 and 15 years.
  • Impetigo is most common in children between the ages of 2 and 5 years.


  1. Carapetis JR, Steer AC, Mulholland EK, Weber M. The global burden of group A streptococcal diseasesexternal icon. Lancet Infect Dis. 2005;5(11):685–94.


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