Strep A: how many cases of scarlet fever and iGAS have there been in 2022 compared to 2018 outbreak?
Strep A infections have led to the deaths of 15 children across the UK. But how widespread is the bug and how does the latest outbreak compare with previous years?
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Strep A, or Group A Streptococcus (GAS), is the name given to a type of bacteria sometimes found in the throat or on the skin. It usually causes mild illnesses such as a sore throat, but can cause other infections such as pneumonia, scarlet fever, cellulitis or impetigo. Very rarely it can cause severe illness when the bacteria get inside the bloodstream. This is called invasive Group A Streptococcal disease (iGAS) and can be deadly.
Are Strep A and scarlet fever at record levels in the UK this year?
Peaks in Strep A infections are typically seen during the winter and spring months. Roughly every three to four years, the UK will see a season of high infection rates.
Scarlet fever is a highly contagious infection caused by the Strep A bacteria. Symptoms include a sandpapery skin rash and a white coating on the tongue.
So far this year, just over 23,000 cases have been reported to the authorities. The same period in 2018 saw 30,600 reports.
What is different with this outbreak is the time of year it is happening. Usually, scarlet fever infections rise in the new year, but this year it began in autumn.
According to the UK Health Security Agency, in the 12 weeks from 12 September to 4 December, there have been 6,601 notifications of scarlet fever in England. This compares to a total of 2,538 in the same period during the 2017/18 winter.
In Northern Ireland, scarlet fever cases have eclipsed the previous peak seen in the 2017/18 winter. There were 125 cases reported last month, compared with the previous high of 97 cases in March 2018.
Scarlet fever rates dipped considerably across the UK during the coronavirus pandemic, due to social distancing restrictions and increased hygiene precautions such as handwashing.
Public health authorities are investigating the rise in cases but do not believe any new strains of Strep A are circulating, instead putting the rise down to increased levels of the bacteria in circulation and more social mixing.
The UK Health Security Agency said the increase is likely to reflect increased susceptibility to these infections in children due to low numbers of cases during the pandemic.
Are there more cases of invasive Group A Strep infections?
Cases of iGAS must be reported to public health authorities in England, Wales and Scotland, but not Northern Ireland. The number of reported cases is high this year but is not at unprecedented levels. High case numbers were also seen in 2018.
In Scotland, while Strep A infections are on the rise, the number of cases of iGAS remain stable and similar to previous years. Last month, there were about 25 iGAS cases across all age groups, according to Public Health Scotland, compared to between 30 and 55 cases during peaks in previous years.
How many people die each year from Strep A?
The invasive version of Strep A infection, iGAS, can be deadly. Parents are being urged to seek medical help if their child is deteriorating after a bout of scarlet fever, a sore throat, or a respiratory infection.
Since September 12, 60 people have died from iGAS across England including, tragically, 13 people aged under 18. At least one child has also died in Wales and one in Northern Ireland.
However, this is still below the number of deaths seen in the 2017/18 outbreak. In England, a total of 355 people died from iGAS in the year ending September 2018, according to the UK Health Security Agency. This included 27 deaths of under-18s.
One difference this year is that a greater proportion of the people dying have been young. In the past five years, around one in 10 people dying from iGAS (9%) in England have been aged under 15. Since September 12 of this year, it has been one in five (22%).
Where have cases of invasive Group A Strep been reported?
In England and Wales, weekly figures published by the UK Health Security Agency show where cases of iGAS have been reported. In the past 10 weeks, Yorkshire and the Humber is the region which has seen the highest rate of cases, with 1.4 cases per 100,000 people.
In the week ending December 11, 15 cases were reported across England and Wales. These were in the following local authority areas:
- Bromley, London (2)
- Dudley, West Midlands (2)
- Wiltshire, South West (1)
- Wandsworth, London (1)
- Powys, Wales (1)
- Merton, London (1)
- Harrogate, North Yorkshire (1)
- Greenwich, London (1)
- Cherwell, Oxfordshire (1)
- Chelmsford, Essex (1)
- Carmarthenshire, Wales (1)
- Bristol City, South West (1)
- Ashfield, Nottinghamshire (1)
The week before, 10 cases were reported across England and Wales. There was one case each in the following local authority areas:
- Bromley, London
- Hillingdon, London
- Hounslow, London
- Lewes, East Sussex
- Newport, Wales
- Plymouth, Devon
- Rochdale, Greater Manchester
- South Holland, Lincolnshire
- Stafford, Staffordshire
In Scotland, public health authorities do not have to be notified of iGAS cases.
Which areas of the UK have the most scarlet fever cases?
Scarlet fever is a notifiable disease in England, Wales and Northern Ireland, meaning medics must report cases to the relevant public health authorities. It is not a notifiable disease in Scotland, so official figures don’t exist.
In England and Wales last week, County Durham was the council area reporting the most cases of scarlet fever, with 101. This was followed by Cardiff, with 100 cases, and Caerphilly, with 76 cases.
No breakdown by local area is published in Northern Ireland.
Have there been any deaths from scarlet fever?
Scarlet fever used to be a very serious infection, but thanks to antibiotics most cases these days are mild and easily treated. Mortality figures for England and Wales show no deaths from scarlet fever in recent years.
However, in very rare occasions, the bacteria that causes scarlet fever - Strep A - can get into the bloodstream and cause the potentially deadly illness iGAS.