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Journal article

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

Abstract:

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.

Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1093/cei/uxad013

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Institution:
University of Oxford
Role:
Author
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Institution:
University of Oxford
Division:
MSD
Department:
Paediatrics
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Author
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Institution:
University of Oxford
Role:
Author
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Institution:
University of Oxford
Role:
Author
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Institution:
University of Oxford
Role:
Author


Publisher:
Oxford University Press
Journal:
Clinical and Experimental Immunology More from this journal
Volume:
211
Issue:
3
Pages:
280–287
Publication date:
2023-02-02
Acceptance date:
2023-01-27
DOI:
EISSN:
1365-2249
ISSN:
0009-9104


Language:
English
Keywords:
Pubs id:
1318214
Local pid:
pubs:1318214
Deposit date:
2023-01-24
ARK identifier:

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