Data show the rate of iGAS is higher this year than it was pre-pandemic for children aged between one and nine years old.
There have been almost 16,000 cases of scarlet fever in England in the last 12 months and 1,766 cases of iGAS.
For the last two winters, there have been very few seasonal viruses circulating, with social isolation measures enforced as a result of the Covid pandemic ensuring other infectious diseases did not spread.
“I don’t think there’s a lack of immunity. I don’t think that children are more likely to get [Strep A] than before, I just think that we haven’t seen it,” Dr Liz Whittaker, a consultant in paediatric infectious diseases at Imperial College healthcare, told The Telegraph.
An individual’s risk from the virus is the same as pre-pandemic, she added, but their exposure is higher now due to it circulating freely for the first time in several years.
Another expert also told The Telegraph: “Now that everything’s going back to normal we are going to see these cases coming back just like we did before the pandemic.
“There may be a few more cases now than there would have been before [Covid] because all these kids didn’t get any infection during the pandemic and therefore there are more kids around who haven’t had it.
“If this had been spread over three years it may not be as high at all but because they’re all getting it together it looks like there’s a lot more infections.”