Ministers have raised the prospect of UK children being given antibiotics as a precaution if a classmate falls ill with a Strep A infection, as they seek to allay parents’ fears following nine deaths.

Group A Streptococcus is a bacteria that can cause strep throat and scarlet fever, as well as skin infections. In a small proportion of cases, bacteria can enter the bloodstream of infected children and cause sepsis or chest, bone or joint infections or abscesses.

In its most recent update, the UK Health Security Agency on Friday said there were 851 cases of scarlet fever reported in the week to November 20, compared with an average of 186 in recent years. The unexpected rise in cases has sparked concerns that children may have failed to build up immunity during the Covid-19 pandemic as they normally would have done.