Six children have died with an invasive condition caused by Strep A – including five under 10-year-olds in England since September – the UK Health Security Agency has said.
A girl from Wales has also died. No deaths have been confirmed in Scotland or Northern Ireland.
Strep A infections are normally mild but people can become seriously ill..
While still uncommon, there has been an increase in invasive Group A Strep cases this year, particularly in children under 10.
Less mixing between children due to the pandemic could have caused a drop in immunity to infections such as Strep A, a leading expert has suggested.
Microbiologist Dr Simon Clarke, from the University of Reading, said he wasn’t aware of any evidence of a new strain but suggested the COVID pandemic might have contributed to an increase in cases.
“It strikes me that as we are seeing with flu at the moment, lack of mixing in kids may have caused a drop in population-wide immunity that could increase transmission, particularly in school age children,” said Dr Clarke.
He said the cases didn’t appear to be linked – they are not clustered around any one area – but he believes “further cases over the coming weeks and months” are likely.
A child from Ealing, west London, and another from Ashford in Surrey, are among those who have died after contracting the infection.
Infections caused by Group A Strep bacteria are usually mild with symptoms like a sore throat or skin infections.
The bug can also cause scarlet fever which can, in the majority of cases, be treated successfully with antibiotics and people make a full recovery.
However, in a very small number of cases, Group A Strep infection can get deeper into the body – for example, into the lungs and bloodstream – causing an illness known as invasive Group A Streptococcus (iGAS), which is much harder to treat.
There are a range of symptoms which may be a sign of an invasive infection, including high fever, poor appetite, dehydration, altered behaviour and feeling very sleepy, according to Dr Colin Brown, deputy director of the UKHSA.
He has advised parents to be on the lookout for these signs and “see a doctor as quickly as possible so that their child can be treated and we can stop the infection becoming serious”.
“Make sure you talk to a health professional if your child is showing signs of deteriorating after a bout of scarlet fever, a sore throat, or a respiratory infection,” he added.