Investigating the association between COVID-19 vaccination and care home outbreak frequency and duration by Bradley, DT, Murphy, S, McWilliams, P, Arnold, S, Lavery, S, Murphy, J, de Lusignan, S, Hobbs, R, Tsang, RSM, Akbari, A, Torabi, F, Beggs, J, Chuter, A, Shi, T, Vasileiou, E, Robertson, C, Sheikh, A, Reid, H, O'Reilly, D