Persistence of the immune response after two doses of ChAdOx1 nCov-19 (AZD1222): 1 year of follow up of two randomised controlled trials

Persistence of the immune response after two doses of ChAdOx1 nCov-19 (AZD1222): 1 year of follow up of two randomised controlled trials

<p>The trajectory of immune responses following the primary dose series determines the decline in vaccine effectiveness over time. Here we report on maintenance of immune responses during the year following a two-dose schedule of ChAdOx1 nCoV-19/AZD1222, in the absence of infection, and also e...

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Hlavní autoři: Voysey, M, Flaxman, A, Aboagye, J, Aley, PK, Belij-Rammerstorfer, S, Bibi, S, Bittaye, M, Cappuccini, F, Charlton, S, Clutterbuck, EA, Davies, S, Dold, C, Edwards, NJ, Ewer, K, Faust, SN, Folegatti, PM, Fowler, J, Gilbride, C, Gilbert, SC, Godfrey, L, Hallis, B, Humphries, HE, Jenkin, D, Kerridge, S, Mujadidi, YF, Plested, E, Ramasamy, MN, Robinson, H, Sanders, H, Snape, MD, Song, R, Thomas, KM, Ulaszewska, M, Woods, D, Wright, D, Pollard, AJ, Lambe, T
Médium: Journal article
Jazyk:English
Vydáno: Oxford University Press 2023
Popis
Shrnutí:<p>The trajectory of immune responses following the primary dose series determines the decline in vaccine effectiveness over time. Here we report on maintenance of immune responses during the year following a two-dose schedule of ChAdOx1 nCoV-19/AZD1222, in the absence of infection, and also explore the decay of antibody after infection. Total spike-specific IgG antibody titres were lower with two low doses of ChAdOx1 nCoV-19 vaccines (two low doses) (P = 0.0006) than with 2 standard doses (the approved dose) or low dose followed by standard dose vaccines regimens. Longer intervals between first and second doses resulted in higher antibody titres (P < 0.0001); however, there was no evidence that the trajectory of antibody decay differed by interval or by vaccine dose, and the decay of IgG antibody titres followed a similar trajectory after a third dose of ChAdOx1 nCoV-19. Trends in post-infection samples were similar with an initial rapid decay in responses but good persistence of measurable responses thereafter. Extrapolation of antibody data, following two doses of ChAdOx1 nCov-19, demonstrates a slow rate of antibody decay with modelling, suggesting that antibody titres are well maintained for at least 2 years. These data suggest a persistent immune response after two doses of ChAdOx1 nCov-19 which will likely have a positive impact against serious disease and hospitalization.</p>

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