Strep A has now killed nine children across the UK amid surging cases of illness linked to the bacterial infection.
The UK Health Security Agency said infections are five times higher than average.
But what is strep A and how can you spot signs of an infection?
What is Strep A?
Strep A is a group of bacteria that can cause skin, soft tissue and respiratory tract infections, which are treated with antibiotics. Illness caused by the bacteria is usually mild, but infections can become serious and systemic.
Group A bacteria can colonise the throat, resulting in an infection called strep throat, which is painful and can create red spots in the area at the back of the roof of the mouth, and white patches or streaks of pus on the tonsils. Other symptoms include fever, a headache and a rash.
The bacterial infection can also result in another illness called scarlet fever, which begins with a high temperature, a sore throat and swollen glands.
A rash, which spreads and feels like sandpaper, appears 12 to 48 hours later on the chest and tummy. The tongue can also look bright red like a strawberry.
Strep A can also cause a skin infection called impetigo, which begins with red, itchy sores that break open and leak pus for a few days before crusting over.
Any group A strep illness can result in invasive infections that spread into deep tissues and the bloodstream. Symptoms include fever and chills, muscle aches, nausea and vomiting, low blood pressure, a fast heart rate, rapid breathing and organ failure.
Streptococcal toxic shock syndrome, as it is known, is extremely serious and can kill.
What are the warning signs of a worsening infection?
Experts have said if a child's health deteriorates to the point where they are “not eating, drinking, being quite flat and lethargic” parents should consult a doctor as soon as possible.
Why are there more cases of Strep A around now?
Scientists think causes are mixed.
“Firstly, I think that we’re seeing a lot of viral infections circulate at the moment and these bacterial infections can come as an addition on top,” Dr Susan Hopkins, chief adviser to the UK Health Security Agency, told BBC Radio 4 on Monday.
“Secondly, we’re back to normal social mixing and the patterns of diseases that we are seeing in the last number of months are out of sync with the normal seasons as people mix back to normal and move around and pass infections on.”
She said the agency is exploring the fact there could be lower than normal immunity to the bacteria due to measures to combat the pandemic.
“We expect that a certain amount of children will have these infections each year and, therefore, they will have a level of immunity. So we’re seeing more now than we have seen for the last two years where there were very, very low amounts of infection seen,” she said.