The UK Health Security Agency issued a rare alert on Friday, telling parents to look out for signs of strep A infection in their children. Since September, eight children in England and Wales have died after becoming unwell with Group A streptococci bacteria. Typically causing illnesses like skin infections, tonsillitis or scarlet fever, very occasionally strep A can become a life-threatening, invasive disease. But why are we seeing such a steep rise in cases in the UK this year? Madeleine Finlay speaks to Chrissie Jones, associate professor of paediatric infection at the University of Southampton, about the significance of this outbreak and the symptoms to be aware of, and asks Shiranee Sriskandan, professor of infectious diseases at Imperial College London, about how the bacteria can evade our immune systems and whether we may one day have a vaccine.. Help support our independent journalism at theguardian.com/sciencepod