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Outbreaks and Public Health Response

Investigating clusters and outbreaks

State, tribal, local and territorial public health officials may investigate clusters or outbreaks of invasive group A Streptococcus (group A strep) infections.

In long-term care facilities

The most common clusters investigated in the United States are those occurring in long-term care facilities (LTCFs).

Controlling Outbreaks in Long-term Care Facilities
CDC investigation tools

Personnel at health departments and LTCFs can use these tools to investigate and control group A strep infections in LTCFs.

In other settings

Other types of outbreak investigations include:

  • Clusters of strep throat among school-aged children
  • Healthcare-associated infections, such as postpartum and post-surgical infections
  • Foodborne outbreaks of strep throat, although these are rare in the United States

These clusters often require urgent public health action.

Requesting CDC support

CDC is available to assist state, tribal, local, and territorial health departments for GAS outbreaks, particularly for persistent, large, or severe outbreaks. For assistance with GAS outbreaks, contact

Learn more about CDC’s Streptococcus Laboratory and requirements for submitting testing requests.

Outbreak control measures


There is currently no vaccine to prevent group A strep infections, although several vaccines are in development.


Prophylaxis (pro-fuh-LAK-sis) is when healthcare professionals give antibiotics to someone to prevent them from getting sick. Most people who are exposed to someone with a group A strep infection should not receive prophylaxis. However, in some situations, healthcare professionals may recommend prophylaxis for someone exposed to an invasive group A strep infection. Invasive group A strep infections include pneumonia, necrotizing fasciitis, and streptococcal toxic shock syndrome.