Public Health Response for Outbreaks

Key points

  • Group A Streptococcus (group A strep bacteria) can cause serious and deadly clusters or outbreaks.
  • U.S. outbreaks occur in many settings but are most common in long-term care facilities (LTCFs).
  • Public health officials may investigate outbreaks to determine how to best control spread and prevent future infections.
Children playing in a pre-school setting.

The problem

Group A strep bacteria can cause clusters and outbreaks of invasive disease. Invasive disease refers to when bacteria invade parts of the body, like blood, that are normally free from germs.

Invasive group A strep disease can include:

In long-term care facilities

The most common clusters and outbreaks investigated in the United States occur in LTCFs.

Group A strep outbreaks in LTCFs need to be investigated‎

CDC has developed tools to help personnel at health departments and LTCFs investigate and control group A strep infections in LTCFs.

In other settings

Other types of investigations include:

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

These clusters or outbreaks often require urgent public health action.

Outbreak control measures

State, tribal, local, and territorial public health officials may investigate clusters or outbreaks of invasive group A strep infections. The goal is generally to determine what measures can control spread, thus preventing future infections. Control measures vary depending on the setting.

Infection control practices

In healthcare settings, infection prevention and control are critical for preventing group A strep outbreaks. Strengthening infection control practices is key to interrupting transmission of group A strep in ongoing outbreaks.


Most people exposed to someone with a group A strep infection don't require prophylaxis (antibiotics given to prevent illness). However, in some situations, prophylaxis may be recommended for someone exposed to an invasive group A strep infection.


There is currently no vaccine to prevent group A strep infections. Several vaccines are in development though.

A coordinated approach

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

CDC's Streptococcus Laboratory serves U.S. health departments with characterizing streptococcal isolates for outbreak support. There are requirements for submitting testing requests.


Vaccine development

Streptococcus pyogenes: World Health Organization

Walkinshaw DR, Wright MEE, Mullin AE, Excler JL, Kim JH, Steer AC. The Streptococcus pyogenes vaccine landscape. NPJ Vaccines. 2023;8(1):16.