Voysey, M., Clemens, S., Madhi, S., Weckx, L., Folegatti, P., Aley, P., Angus, B., Baillie, V., Barnabas, S., Bhorat, Q., Bibi, S., Briner, C., Cicconi, P., Clutterbuck, E., Collins, A., Cutland, C., Darton, T., Dheda, K., Dold, C., Duncan, C., Emary, K., Ewer, K., Flaxman, A., Fairlie, L., Faust, S., Feng, S., Ferreira, D., Finn, A., Galiza, E., Goodman, A., Green, C., Green, C., Greenland, M., Hill, C., Hill, H., Hirsch, I., Izu, A., Jenkin, D., Joe, C., Kerridge, S., Koen, A., Kwatra, G., Lazarus, R., Libri, V., Lillie, P., Marchevsky, N., Marshall, R., Mendes, A., Milan, E., Minassian, A., McGregor, A., Mujadidi, Y., Nana, A., Padayachee, S., Phillips, D., Pittella, A., Plested, E., Pollock, K., Ramasamy, M., Ritchie, A., Robinson, H., Schwarzbold, A., Smith, A., Song, R., Snape, M., Sprinz, E., Sutherland, R., Thomson, E., Török, M., Toshner, M., Turner, D., Vekemans, J., Villafana, T., White, T., Williams, C., Douglas, A., Hill, A., Lambe, T., Gilbert, S. & Pollard, A. 2021, 'Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials', The Lancet, 397(10277), pp. 881-891. http://dx.doi.org/10.1016/S0140-6736(21)00432-3