"an algorithm has identified another 1.7 million adults in England that are to be added to the shielding list and prioritised for vaccination. Using medical records and other characteristics (including age, ethnicity, housing status and postcode), it assigns a risk score out of 100, and the people with the highest scores are added to the shielding list. To see more on how the risk prediction model works, the University of Oxford has published the QCovid calculator.”