About this release

Our quarterly update

This release by Public Health Scotland (PHS) provides quarterly information on Group A Streptococcal (GAS) infections.

In Scotland, GAS infections are monitored using routine laboratory data.

Under the Public Health (Scotland) Act 2008, cases of invasive GAS (iGAS) are notifiable but scarlet fever is not notifiable in Scotland.

Culture and PCR-positive GAS and iGAS specimens from all laboratories in Scotland are submitted to PHS using the Electronic Communication of Surveillance in Scotland (ECOSS) system.  

GAS infections are classified as invasive if they have been isolated by culture or accredited molecular methods (such as PCR) from a normally sterile body site, such as:

  • blood
  • cerebrospinal fluid
  • joint aspirate
  • pericardial peritoneal-pleural fluids
  • bone
  • endometrium
  • deep tissue or deep abscess at operation or post-mortem

An iGAS-related death is defined as death (from all causes) within seven days of a positive iGAS specimen. PHS actively follows up outcomes for all reported cases after 30 days to make sure they are captured. 

iGAS cases are also reported to PHS using an enhanced surveillance questionnaire, which provides further information on risk factors and outcomes.

Invasive GAS samples are also sent to the Scottish Microbiology Reference Laboratory (SMiRL) for further analysis and typing.

Next release

The next release of this publication will be 27 August 2024.

Main points

Activity

In Quarter 1 (Jan to Mar) 2024 there was:

  • a reduction in iGAS cases of 47.2% (103 cases) when compared with Quarter 1 2023 (195 cases)
  • an increase of 39.2% when compared with Quarter 4 (Oct to Dec) 2023 (74 cases)

Age

In Quarter 1 2024 the largest proportion of iGAS cases were in adults:

  • aged 65 years and older (34.0% or 35 out of 103 cases)
  • aged 45 to 64 years (28.2% or 29 out of 103 cases)

This compares with Quarter 1 of 2023 where the largest proportions were in adults aged 65 years and older (36.4%) followed by 15 to 44 years and 45 to 64 years (both 23.6%).

Location

In Quarter 1 2024 most iGAS cases were reported from NHS Greater Glasgow and Clyde (21.4% or 22 out of 103 cases ) followed by:

  • NHS Lothian – 16.5% or 17 out of 103 cases
  • NHS Grampian – 10.7% or 11 out of 103 cases

Mortality

The percentage of iGAS cases reported to have died was 7.8% (8 out of 103 cases).

This is within the range of 5.6% to 12.0% reported to have died annually between 2018 and 2023.

Typing

Emm typing was available for 71.8% (74 out of 103 cases) of iGAS cases.

Of these, emm type 3.93 accounted for 20.3% (15 out of 64 cases) of iGAS cases typed, followed by:

  • emm type 1.0 – 12.2% or 9 out of 74 cases
  • emm type 76.0 – 8.1% or 6 out of 74 cases

Results and commentary

Overall, iGAS case numbers vary year to year with peaks usually observed during the winter and spring months.

Data in this report are published quarterly (every 13 weeks) and comprise iGAS laboratory reports submitted to ECOSS from NHS diagnostic laboratories and the Scottish Microbiology Reference Laboratory (SMiRL).

Please note that the data presented in this update are provisional and subject to change as data continue to be received.  

General trend

In Quarter 1 (Jan to Mar, weeks 1 to 13) 2024, there were 103 reports of GAS isolated from a normally sterile site (iGAS cases) (Figure 1).

This is a reduction of 47.2% when compared with Quarter 1 2023 (195 cases) but an increase of 39.2% when compared with Quarter 4 (Oct to Dec, weeks 40 to 52) 2023 (74 cases).

The iGAS case numbers in Quarter 1 between 2017 and 2024 have ranged from 11 cases (in 2021) to 195 cases (in 2023).

Image caption Figure 1: Number of invasive Group A streptococcus (iGAS) cases by quarter, 2017 to quarter 1 2024, Scotland

Age

In Quarter 1 2024, most iGAS cases were reported in adults aged 65 years and above (34.0% or 35 out of 103 cases) (Figure 2).

This is followed by those aged:

  • 45 to 64 years – 28.2% (29 out of 103 cases)
  • 15 to 44 years – 23.3% (24 out of 103 cases)
  • 0 to 14 years – 14.6% (15 out of 103 cases)

In comparison, age distribution in Quarter 1 2023 showed most cases in those aged 65 years and over (36.4% or 71 out of 195 cases).

This was followed by those aged:

  • 45 to 64 years – 23.6% (46 out of 195 cases)
  • 15 to 44 years – 23.6% (46 out of 195 cases)
  • 0 to 14 years – 16.4% (32 out of 195 cases)
Image caption Figure 2: Number of invasive Group A Streptococcus (iGAS) cases by age group, year and quarter, 2017 to quarter 1 2024, Scotland

NHS board

In Quarter 1 (Jan to Mar) 2024, iGAS cases were reported from all NHS boards except:

  • NHS Orkney
  • NHS Shetland
  • NHS Western Isles

Most iGAS cases were reported from NHS Greater Glasgow and Clyde (21.4% or 22 out of 103 cases) followed by:

  • NHS Lothian – 16.5% (17 out of 103 cases)
  • NHS Grampian – 10.7% (11 out of 103 cases)

This compares to Quarter 1 2023 with:

  • NHS Greater Glasgow and Clyde – 21.0% (41 out of 195 cases)
  • NHS Lothian – 15.4% (30 out of 195 cases)
  • NHS Lanarkshire – 11.8% (23 out of 195 cases)
Image caption Figure 3: Number of invasive Group A Streptococcus (iGAS) cases by NHS board, year and quarter, 2017 to quarter 1 2024, Scotland

iGAS deaths

In Quarter 1 2024, the percentage of iGAS cases that were reported to have died was 7.8% (8 out of 103 cases).

This is lower than the percentage reported to have died in 2023 (12.0% or 56 out of 465 cases) and within the range of 5.6% to 12.0% reported annually since 2018 (Table 1).

Most of the deaths in Quarter 1 2024 were in adults aged:

  • 65 years and older – 63.6% (5 out of 8 cases)
  • 45 to 64 years – 25.0% (2 out of 8 cases)

The highest case fatality rate (CFR) was also observed in adults aged:

  • 65 years or older – 14.3% (5 out of 35 cases)
  • 45 to 64 years – 6.9% (2 out of 29 cases)

Table 1: laboratory-confirmed iGAS CFR by season 

Source: PHS ECOSS/iGAS enhanced surveillance database

Year Number of cases Number of deaths CFR%
2018 381 34 8.9
2019 262 21 8.0
2020 180 10 5.6
2021 64 4 6.3
2022 281 18 6.4
2023 465 56 12.0
2024* 103 8 7.8
References

*Data to Quarter 1 (Jan to Mar) 2024 only

iGAS emm types

Analysis of reference laboratory typing of isolates shows that in Quarter 1 2024, emm typing was available for 71.8% (74 out of 103 cases) of iGAS cases and identified 29 different types.

Emm type 3.93 accounted for 20.3% (15 out of 74 cases) of iGAS cases typed (Table 2a), followed by:

  • emm type 1.0 – 12.2% (9 out of 74 cases)
  • emm type 76.0 – 8.1% (6 out of 74 cases)

This reflects a change from 2023 (Table 2b) when emm type 1.0 was the most commonly identified emm type (56.0% or 204 out of 364 cases) followed by:

  • emm type 12.0 (23 out of 364)
  • emm type 89.0 (18 out of 364 cases)

Table 2a: number and proportion invasive Group A Streptococcus (iGAS) laboratory reports by emm type, Quarter 1 2024, Scotland

Source PHS ECOSS

emm type Number typed Q1 2024 Percentage (%)
3.93 15 20.3
1.0 9 12.2
76.0 6 8.1
4.0 5 6.8
3.1 4 5.4
77.0 4 5.4
Others (<4 per emm type) 31 41.9
Total 74
References

Total percentage may not add to 100 due to rounding

Table 2b: number and proportion of invasive Group A Streptococcus (iGAS) laboratory reports by emm type 2023, Scotland. 

Source: PHS ECOSS

emm type Number in 2023 Percentage (%)
1.0 204 56.4
12.0 23 6.3
89.0 18 4.9
76.0 14 3.8
4.0 9 2.5
1.25 8 2.2
28.0 8 2.2
87.0 7 1.9
12.37 6 1.6
3.93 5 1.4
75.0 5 1.4
108.1 4 1.1
11.0 4 1.1
77.0 4 1.1
82.0 4 1.1
Other (<4 per emm type) 41 11.3
Total 364

Discussion

Overall activity

The number of iGAS cases reported in Quarter 1 (Jan to Mar) 2024 (103 cases) reduced by 47.2% when compared to Quarter 1 (Jan to Mar) 2023 (195 cases) and is within the range reported in Quarter 1 from 2017 to 2023 (11 to 195 cases).

With the exception of 2017 and 2022, iGAS activity was highest in the first quarter of each year.

As expected with seasonal patterns of iGAS activity, Quarter 1 2024 iGAS case numbers were higher than reported in Quarter 3 (72 cases) and Quarter 4 2023 (74 cases) (Figure 1).

Age

Historically, iGAS cases are more commonly reported in older adults with case numbers increasing with age.

In Quarter 1 2024, most cases were reported in those aged 65 years and above (34.0% or 35 out of 103 cases) and 34 to 64 years (28.2% or 29 out of 103 cases).

When compared with Quarter 1 2023, there were reductions in case numbers reported from all age groups and the largest proportions were in adults aged 65 years and older (36.4%) followed by 15 to 44 years and 45 to 64 years (both 23.6%) (Figure 2).

NHS board activity

In Quarter 1 2024, all NHS boards – except NHS Orkney, NHS Shetland and NHS Western Isles – reported iGAS cases with larger NHS boards reporting most cases (Figure 3):

  • NHS Greater Glasgow and Clyde – 21.4% (22 out of 103 cases)
  • NHS Lothian – 16.5% (17 out of 103 cases)
  • NHS Grampian – 10.7% (11 out of 103 cases)

iGAS mortality

The were 8 deaths among the 103 iGAS cases reported in Quarter 1 2024 with a case fatality rate (CFR) of 7.8%. This is within the range reported annually since 2018 (Table 1).

Most of the deaths (63.6% or 5 out of 8 cases) and the highest CFR (14.3% or 5 out of 35 cases) occurred in adults aged 65 years and above suggesting that older people are more susceptible to iGAS and its complications.

iGAS emm type

In Quarter 1 2024, emm typing was available for 71.8% of cases and 29 different emm types were identified.

Historically, emm type 1 has been the most commonly identified emm type in Scotland.

However, in Quarter 1 2024 the most common was emm type 3.93 (15 cases, 20.3%) followed by:

  • emm type 1.0 – 9 cases (12.2%)
  • emm type 76.0 – 6 cases (8.1%)

The changing distribution of iGAS emm types and any potential impact on transmissibility and disease severity are not yet fully understood.

Contact

General enquiries

If you have an enquiry relating to this publication, please email phs.flu@phs.scot.

Media enquiries

If you have a media enquiry relating to this publication, please contact the Communications and Engagement team.

Requesting other formats and reporting issues

If you require publications or documents in other formats, please email phs.otherformats@phs.scot.

To report any issues with a publication, please email phs.generalpublications@phs.scot.

Further information

Statistical designation

Official Statistics in development are official statistics which are undergoing development and are published in order to involve users and stakeholders in their development and as a means to build in quality at an early stage.

It is important that users understand that limitations may apply to the interpretation of this data, further details of which are presented in this report.

All official statistics should comply with the UK Statistics Authority’s Code of Practice which promotes the production and dissemination of official statistics that inform decision making. Once the evaluation is completed and an enhanced report is developed that meets the needs of users and stakeholders, the 'Official Statistics in development' label will be removed.

Our statistical practice is regulated by the Office for Statistics Regulation (OSR). OSR sets the standards of trustworthiness, quality and value in the Code of Practice for Statistics that all producers of official statistics should adhere to. You are welcome to contact us directly with any comments about how we meet these standards.

Alternatively, you can contact OSR by emailing regulation@statistics.gov.uk or through the OSR website.

Visit the UK Statistics Authority website for more information about the Code of Practice and Official Statistics.

Planned developments

The content of these reports will be reviewed and developed over time following feedback from stakeholders and user engagement. 

Pre-release access

Under terms of the 'Pre-Release Access to Official Statistics (Scotland) Order 2008', PHS is obliged to publish information on those receiving Pre-Release Access ('Pre-Release Access' refers to statistics in their final form prior to publication). The standard maximum Pre-Release Access is five working days.

Shown below are details of those receiving standard Pre-Release Access.

Standard pre-release access

  • Scottish Government Department of Health and Social Care (DHSC)
  • NHS board chief executives
  • NHS board communication leads

About Public Health Scotland (PHS)

PHS is a knowledge-based and intelligence driven organisation with a critical reliance on data and information to enable it to be an independent voice for the public’s health, leading collaboratively and effectively across the Scottish public health system, accountable at local and national levels, and providing leadership and focus for achieving better health and wellbeing outcomes for the population.

Our statistics comply with the Code of Practice for Statistics in terms of trustworthiness, high quality and public value. This also means that we keep data secure at all stages, through collection, processing, analysis and output production, and adhere to the Office for National Statistics ‘Five Safes’ of data privacy.​

Metadata

Publication title

Group A Streptococcus (GAS): quarterly surveillance report

Description

This report describes cases of invasive Group A Streptococcus in Scotland.

Theme

Invasive Group A Streptococcus Infections in Scotland.

Topic

iGAS

Format

HTML

Data source(s)

Electronic Communication of Surveillance in Scotland (ECOSS)

Date that data are acquired

3 May 2024

Release date

28 May 2024

Frequency

Quarterly

Timeframe of data and timeliness

January 2017 to March 2024, approximately two months in arrears.

Continuity of data

Data from 2017 to March 2024 is presented.

Revisions statement

None

Revisions relevant to this publication

None

Concepts and definitions

GAS infections are classified as invasive if they have been isolated by culture or accredited molecular methods (such as PCR) from a normally sterile body site, such as blood, cerebrospinal fluid, joint aspirate, pericardial peritoneal-pleural fluids, bone, endometrium, deep tissue or deep abscess at operation or post-mortem.

An iGAS-related death is defined as death (from all causes) within seven days of a positive iGAS specimen.

Information on laboratory culture-positive reports of all GAS and iGAS infections are routinely submitted to the Electronic Communication of Surveillance in Scotland (ECOSS).

iGAS cases in Scotland are notifiable under the Public Health (Scotland) Act 2008.

Relevance and key uses of the statistics

Data are collected as part of mandatory public health surveillance providing data to monitor the epidemiology of GAS and iGAS, informing public health planning and response. 

Statistics are used by PHS for surveillance purposes and published for transparency. 

Accuracy

The data are considered accurate. 

Data are validated locally by partnerships. 

PHS carries out further validation checks in consultation with NHS Boards, as required. 

The Code of Practice for Statistics has been followed to ensure a high standard of data value, trustworthiness and quality. 

Completeness

All data returned from ECOSS is used for analysis.

Comparability

Scottish data is regularly compared to UKHSA Group A Streptococcal disease data and information.

Accessibility

It is the policy of Public Health Scotland (PHS) to make its web sites and products accessible according to published guidelines.

Coherence and clarity

The report has been produced using the standard PHS publications template and is available as HTML web pages. 

Value type and unit of measurement

Number of invasive Group A Streptococcal cases.

Disclosure

The PHS protocol on statistical disclosure is followed.

Official Statistics accreditation

Official statistics in development.

UK Statistics Authority Assessment

Not assessed.

Last published

Not applicable.

Next published

27 August 2024

Date of first publication

28 May 2024

Help email

phs.flu@phs.scot

Date form completed

7 May 2024

Glossary

CFR

Case fatality rate for iGAS is the proportion of cases of iGAS that die within seven days of a positive specimen regardless of the cause of death.

This enhanced case information is actively followed up 30 days after initial reporting.

ECOSS

Electronic Communication of Surveillance in Scotland system

GAS

Group A Streptococcus

iGAS

Invasive group A streptococcal infections

NHS

NHSScotland is the publicly funded healthcare system in Scotland and one of the four systems that make up the National Health Service in the United Kingdom.

It operates 14 territorial NHS boards across Scotland, supported by seven special non-geographic health boards, and Public Health Scotland.

Public Health Scotland is Scotland’s lead national body for improving and protecting the health and wellbeing of all of Scotland’s people. It is an NHS board that is uniquely sponsored by the Scottish Government and the Convention of Scottish Local Authorities (COSLA).

PCR

Polymerase chain reaction (PCR) is a technique used to make numerous copies of a specific segment of DNA quickly and accurately.

Quarter 1

This covers January to March (weeks 1 to 13).

Quarter 2

This covers April to June (weeks 14 to 26).

Quarter 3

This covers July to September (weeks 27 to 38).

Quarter 4

This covers October to December (weeks 39 to 52).

Last updated: 28 May 2024
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