Immunogenicity and safety of AZD2816, a beta (B.1.351) variant COVID-19 vaccine, and AZD1222 (ChAdOx1 nCoV-19) as third-dose boosters for previously vaccinated adults: a multicentr... by Ramasamy, MN, Kelly, EJ, Seegobin, S, Dargan, PI, Payne, R, Libri, V, Adam, M, Aley, PK, Martinez-Alier, N, Church, A, Jepson, B, Khan, M, Matthews, S, Townsend, GT, Vekemans, J, Bibi, S, Swanson, PA, Lambe, T, Pangalos, MN, Villafana, T, Pollard, AJ, Green, JA