Group A Streptococcus

Information and guidance on group A streptococcal infections.

This group A Streptococcus collection also contains information on:

Infection and symptoms

Group A Streptococcus (also known as GAS, group A strep, strep A, and Streptococcus pyogenes) is a bacterium which can colonise the throat, skin and anogenital tract. It is spread by close contact between individuals, through respiratory particles and direct skin contact. It can also be transmitted environmentally, for example through contact with contaminated objects, such as towels or bedding, or ingestion of food prepared by someone with the infection.

GAS causes a diverse range of skin, soft tissue and respiratory tract infections, including:

Occasionally these infections can be extremely severe.

Scarlet fever is characterised by a rash, which usually accompanies a sore throat. Cases may also have a red and swollen tongue and flushed cheeks.

Invasive GAS (iGAS) is another infection caused by GAS, that is much rarer than scarlet fever. It occurs when GAS is isolated from a normally sterile body site, such as the blood.

Both iGAS and scarlet fever are notifiable diseases; health professionals must inform local health protection teams (HPTs) of suspected cases.

Information for the public

Members of the public can seek advice about group A streptococcal infections from the following resources:

The latest UK Health Security Agency (UKHSA) updates for the public are also available on GOV.UK:

Guidance for professionals

Guidelines on antimicrobial prescribing for acute sore throat are set out in the National Institute for Health and Care Excellence (NICE) guidance [NG84]: Sore throat (acute): antimicrobial prescribing.

Due to rapidly increasing rates of GAS infections in children at the end of 2022, NHS England (NHSE) published interim clinical guidance on the diagnosis and treatment of children with GAS on 9 December 2022, which superseded the NICE guidance. In light of the decrease in rates of infection subsequently seen in early 2023, the NICE guidance has been reinstated and the interim guidance was withdrawn on 16 February 2023, as outlined in a statement from NHSE.

Prevention and control of group A streptococcal infection in acute healthcare and maternity settings in the UK was published in 2011 by the Health Protection Agency.


GAS is formally diagnosed by microbiological culture of samples taken from the affected site. Serology has specific clinical uses and can be discussed with a local infection specialist. GAS isolates from patients with healthcare-associated infections should be stored locally for a minimum of 6 months.

Epidemiology and reports

Working with UKHSA, Public Health Scotland, Public Health Agency (Northern Ireland), and the National Child Mortality database, Public Health Wales (PHW) published on 4 March 2024 a rapid review into iGAS deaths in children outside of hospital that occurred at the end of 2022 and in early 2023. 

The Four nations rapid review of iGAS deaths in children can be accessed on the PHW website.

Previous activity reports on group A streptococcal infections were published by Public Health England. The following are UKHSA reports.

Updates to this page

Published 31 July 2014
Last updated 20 November 2023 + show all updates
  1. Added Group A streptococcal infections: report on seasonal activity in England, 2023 to 2024.

  2. Updated guidance for professionals and added links to NICE guidelines on antimicrobial prescribing for sore throat and NHS England statement on withdrawal of interim guidance.

  3. Updated background information and provided links for people seeking medical advice.

  4. Added Group A streptococcal infections: activity during the 2022 to 2023 season.

  5. Added Group A streptococcal infections: activity during the 2021 to 2022 season.

  6. Added link 'Invasive group A streptococcal outbreaks associated with home healthcare'.

  7. Updated link under Diagnosis to AMRHAI, which now provides diagnostic services.

  8. Added 'Group A streptococcal infections: activity during the 2018 to 2019 season' document.

  9. Latest seasonal activity document inserted into the Epidemiology subgroup (2017/2018 season)

  10. Added report on activity during the 2014 to 2015 season under epidemiology.

  11. Added 'Group A streptococcal infections: activity during the 2014 to 2015 season' to the collection.

  12. First published.