Guidance

Accessible text versions of the 4 algorithms

Updated 7 March 2023

These are accessible text versions of the 4 algorithms which appear in the ‘UK guidelines for the management of contacts of invasive group A streptococcus (iGAS) infection in community settings’.

Algorithm 1. Management of contacts of a case of iGAS in a household-type setting

Algorithm 1 consists of 9 steps containing 4 yes-no questions and 4 notes.

The process begins with the identification of iGAS infection in a household-type setting.

(Note 1: invasive GAS infection (iGAS) is defined through isolation of GAS from a normally sterile body site. GAS isolated from non-sterile site in combination with severe clinical presentation should be managed as per iGAS.)

Two actions follow:

a) Local microbiology laboratory to save isolate for 6 months and send directly to reference laboratory.

b) Consider if any source or setting needs to be noted and added on HPZone as a context, such as community health care, recent prison, and so on.

c) Notify local health protection team urgently.

Question 1. Were there any close contacts?

(Note 2: close contact is defined as someone who has had prolonged close contact with the case in a household-type setting during the 7 days before diagnosis of iGAS infection. Examples include those living and/or sleeping in the same household, pupils in the same dormitory, intimate partners, or university students sharing a kitchen in a hall of residence. Consider contacts who provide nursing care (district nurses, health visitors).

If no, no further investigation.

If yes, go to Question 2.

Question 2: Anyone diagnosed with confirmed or probable iGAS infection in previous 30 days?

If yes, offer chemoprophylaxis to entire household as soon as possible via primary or secondary care or out-of-hours service, and provide factsheet.

If no, go to Question 3.

Question 3: Are there any high-risk contacts? These include:

• age 75 or over
• neonate 28 days or under
• late pregnancy (37 weeks or more) or post-partum (28 days or less)
• chickenpox open lesions in 7 days prior to iGAS diagnosis in the case or within 48 hours after commencing antibiotics by the iGAS case, if exposure ongoing

If yes, offer chemoprophylaxis to high risk contact via GP or out-of-hours service (if within 10 days of iGAS diagnosis in the index case). Then go to Question 4.

If no, go straight to Question 4.

Question 4: Any contacts with signs and symptoms of possible GAS infection?

If no, go to directly to the final stage in the algorithm: reassure and provide the ‘Warn and inform factsheet’.

If yes, proceed through several steps before reaching the same final stage.

There are 2 courses of action depending on whether the infection is suspected of being invasive or non-invasive.

Route a) Clinically suspected invasive infection.

(Note 4: symptoms suggestive of invasive disease include high fever, severe muscle aches or localised muscle tenderness, with or without a high index of suspicion of invasive disease. In the absence of a more likely alternative diagnosis, then emergency referral to A&E. Contact A&E to advise of incoming patient.)

Route a) consists of 2 parts:

1. Emergency referral to secondary care for immediate medical assessment, followed by:

2. The final stage in the algorithm for all paths: reassure and provide the ‘Warn and inform factsheet’.

Route b) Non-invasive infection.

(Note 3: symptoms suggestive of non-invasive GAS infection include sore throat, fever, minor skin infections, scarlatiniform rash.)

Route b) also consists of 2 parts:

1. Refer symptomatic contact for clinical assessment and treatment.

2. The final stage in the algorithm for all paths: reassure and provide the ‘Warn and inform factsheet’.

End of algorithm 1.

Algorithm 2. Management of iGAS case linked to a nursery, school or other childcare setting

Algorithm 2 consists of 8 steps containing 2 yes-no questions and 5 notes.

The process begins with the identification of iGAS infection in child or staff with attendance at school, nursery or other childcare setting within 7 days of onset.

(Note 1: invasive GAS infection (iGAS) is defined through isolation of GAS from a normally sterile body site. GAS isolated from non-sterile site in combination with severe clinical presentation should be managed as per iGAS. Note 2: where the case hasn’t attended the setting in 7 days before onset, it may be necessary to inform the school, for example, if severe illness or death.)

Two actions follow:

a) Local microbiology laboratory to save isolate for 6 months and send directly to reference laboratory.

b) Notify local health protection team urgently.

Question 1. Conduct risk assessment. Are there other children or staff with either non-invasive GAS infection in the last 7 days OR iGAS in the last 30 days and/or are influenza or chickenpox co-circulating?

(Note 3: symptoms suggestive of non-invasive GAS infection include sore, throat, fever, minor skin infections, scarlatiniform rash. Note 4: symptoms suggestive of invasive disease including high fever, severe muscle aches or localised muscle tenderness with or without high index of suspicion of invasive disease.)

If no, reassure and provide ‘warn and inform’ factsheet to parents in the same class. Nursery or school to establish 30 day surveillance.

(Note 5: prospective 30 day surveillance for GAS, iGAS, chickenpox and influenza.)

If yes, consider convening an OCT.

• identify possible routes of transmission (identify commonality with location, staffing, social or sports groups
• consider targeted swabbing (throat or skin lesions) to identify extent of transmission (refer GAS positive isolates)

Alongside considering convening an OCT, move to the second and final question.

Question 2: Is there co-circulating chickenpox or influenza?

If yes, Consider other control measures for flu or chickenpox:

• consider prophylaxis of children and staff: varicella vaccination or antiviral treatment or prophylaxis for influenza (seek expert advice as necessary)

If no, implement control measures, including:

• review clearning and hygiene practices, implement infection control measures
• inform parents and staff of outbreak
• ensure treatment and exclusion of symptomatic staff or children (until 24 hours treatment received)
• consider communication to local healthcare providers
• review microbiology and surveillance records to identify possible linked GAS cases in the previous 6 months
• nursery or school to establish 30 day surveillance (Note 5: prospective 30 day surveillance for GAS, iGAS, chickenpox and influenza)

End of algorithm 2.

Algorithm 3. Management of a single case of iGAS infection in a care home setting

Algorithm 3 consists of 12 steps containing 2 yes-no questions, one positive or negative option question and 7 notes.

The process begins with the identification of iGAS infection in care home setting.

(Note 1: invasive GAS infection (iGAS) is defined through isolation of GAS from a normally sterile body site. GAS isolated from non-sterile site in combination with severe clinical presentation should be managed as per iGAS.)

(Note 2: invasive GAS infection iGAS) is defined through isolation of GAS from a normally sterile body site. GAS isolated from non-sterile site in combination with severe clinical presentation should be managed as per iGAS.)

Two actions follow:

a) Local microbiology laboratory to save isolate for 6 months and send directly to reference laboratory.

b) Notify local health protection team urgently.

Question 1. Ascertain if the case is care home acquired?

(Note 3: consider care home acquired if symptoms or signs of infection are not present on entry to the care home and there is no other possible source of transmission, for example, from a recent hospital stay.)

If no, if hospital-acquired, manage as per acute healthcare guidelines.

If yes, 2 actions follow:

1. Review microbiology and surveillance records to identify possible linked GAS cases in last 6 months (see algorithm 4 if additional cases are identified).

2. Conduct risk assessment of the home including:

• determine size and layout of the home, number of staff and residents, staffing movements
• if iGAS case is being managed in the home, advise on infection control as per acute healthcare guidelines
• ask care home if there have been iGAS/GAS cases in previous 6 months (see algorithm 4 if additional cases are identified)

Continue on to next step: ensure terminal clean of bathroom and bedroom.

Continue on to question 2: Have there been any contacts with signs and symptoms of possible GAS infection in the previous 7 days?

(Note 4: Carers, peripatetic staff, visitors, other residents with direct contact or close proximity to the case.)

If no, ask care home to report new cases amongst staff and residents in the next 30 days and establish prospective surveillance for 6 months.

If yes, there are 2 courses of action depending on whether the infection is clinically suspected invasive or non-invasive infection.

Route a) Clinically suspected invasive infection

(Note 6: symptoms suggestive of invasive disease include high fever, severe muscle aches or localised muscle tenderness with or without a high index or suspicion of invasive disease. In the absence of a more likely alternative diagnosis then emergency referral to A&E. Contact A&E to advise of incoming patient.)

Continue on to urgent referral to hospital (if not already in hand). (See algorithm 4.)

Route b) Non-invasive infection.

(Note 5: symptoms suggestive of non-invasive GAS infection include sore throat, fever, minor skin infections.)

Route b has 3 further courses of action depending on whether the infection is in staff, residents or visitors.

Route b) Staff: arrange swabbing (thoat or skin lesions), treatment as appropriate and immediate exclusion (until 24 hour treatment received). Route b) ‘Staff’, has 2 further routes, depending on the swab result.

1. Positive swab: see algorithm 4: manage as per acute healthcare guidelines.

2. Negative swab: 30-day active surveillance; passive surveillance for 6 months.

Route b) Residents: GP assessment and treatment and see algorithm 4.

Route b) Visitors: refer to GP.

End of algorithm 3.

Algorithm 4. Management of suspected or confirmed iGAS outbreak in care home

Algorithm 4 consists of 13 steps, containing one yes-no questions and 5 notes.

The process begins with the identification of a suspected or confirmed iGAS outbreak in a care home setting.

(Note 1: An outbreak is defined as 2 or more cases of confirmed or probable iGAS infection related by person or place. These cases will usually be within a month of each other but the interval may extend to several months.)

Three actions follow:

1. Individual cases managed as per algorithm 1.

2. Local health protection team to convene outbreak control team. (Note 3: outbreak control team may include care home manager, consultant microbiologist, occupational health adviser, local GP, local commissioning lead and communications adviser.)

3. Inform and send isolates to reference laboratory. (Note 2: clearly label isolates sent to the reference laboratory as being part of a suspected outbreak to prioritise processing. Epidemiological investigations and preventative measures should not await results of typing.)

Action 2 has 2 further steps:

Step a) implement control measures, including:

• review cleaning and other infection control policies and practices
• take immedication action to rectify and deficiencies
• consider screening and/or prophylaxis of residents and staff
• halt new admission
• seek expert advice where required

Step b) Identify possible source: assessment of common exposures in 7 days prior to onset. (Note 4: assess possible sources according to case’s movements or contacts in the home 7 days prior to onset. Carers, other residents, equipment and the environment are possible sources of outbreaks. Develop timelines and network analyses to identify common exposures, if 2 or more cases.)

Three further actions follow from step b) in order to to support the assessment of common exposures:

1. Care home staff

Identify care home staff with epidemiological link to cases and consider screening (throat and skin lesions) or immediate prophylaxis. (Note 5: care home staff includes carers, peripatetic staff (hairdressers, podiatrists, GPs, district nurses and so on), visitors and other residents with direct contact or close proximity to the case within 7 days prior to diagnosis. Consider kitchen staff.)

2. Residents

Identify residents with epidemiological link to cases or symptoms and consider screening (throat and skin lesions) or immediate prophylaxis.

3. Environment

Identify any common equipment, communal areas visited, bathrooms shared, proximity of bedrooms. Consider environmental sampling or epidemiologically linked equipment or facilities.

This leads onto Question 1: has the source of the outbreak been established?

If yes a) take remedial action and b) undertake enhanced surveillance, including:

• care home to report all further possible cases in staff or residents
• consider screening of residents (if not already done) to identify extent of transmission

If No, consider repeat screening of staff epidemiologically linked to outbreak and screen at other sites (nose, anus and vagina), then repeat Question 1: Has the source of the outbreak been established?

End of algorithm 4.