As back to school looms and in-person teaching returns, there is an expectation that Covid-19 cases will rise, especially among children. In the UK, the Medicines and Healthcare products Regulatory Agency (MRHA) has approved the Moderna and Pfizer vaccines for children aged 12 to 17, but they are still not available to most people in this demographic. Shivani Dave speaks to the Guardian’s science correspondent, Natalie Grover, about why that is the case. Help support our independent journalism at theguardian.com/sciencepod