Viral burden is associated with age, vaccination, and viral variant in a population-representative study of SARS-CoV-2 that accounts for time-since-infection-related sampling bias by Fryer, HR, Golubchik, T, Hall, M, Fraser, C, Hinch, R, Ferretti, L, Thomson, L, Nurtay, A, Pellis, L, House, T, MacIntyre-Cockett, G, Trebes, A, Buck, D, Piazza, P, Green, A, Lonie, LJ, Smith, D, Bashton, M, Crown, M, Nelson, A, McCann, CM, Adnan Tariq, M, Elstob, CJ, Nunes Dos Santos, R, Richards, Z, Xhang, X, Hawley, J, Lee, MR, Carrillo-Barragan, P, Chapman, I, Harthern-Flint, S, Bonsall, D, Lythgoe, KA