Evaluation of the immunogenicity of prime-boost vaccination with the replication-deficient viral vectored COVID-19 vaccine candidate ChAdOx1 nCoV-19.

Graham, Simon P; McLean, Rebecca K; Spencer, Alexandra J; Belij-Rammerstorfer, Sandra; Wright, Daniel; Ulaszewska, Marta; Edwards, Jane C; Hayes, Jack W P; Martini, Veronica; Thakur, Nazia; Conceicao, Carina; Dietrich, Isabelle; Shelton, Holly; Waters, Ryan; Ludi, Anna; Wilsden, Ginette; Browning, Clare; Bialy, Dagmara; Bhat, Sushant; Stevenson-Leggett, Phoebe; Hollinghurst, Philippa; Gilbride, Ciaran; Pulido, David; Moffat, Katy; Sharpe, Hannah; Allen, Elizabeth; Mioulet, Valerie; Chiu, Chris; Newman, Joseph; Asfor, Amin S; Burman, Alison; Crossley, Sylvia; Huo, Jiandong; Owens, Raymond J; Carroll, Miles; Hammond, John A; Tchilian, Elma; Bailey, Dalan; Charleston, Bryan; Gilbert, Sarah C; Tuthill, Tobias J; Lambe, Teresa; Graham, Simon P.; McLean, Rebecca K.; Spencer, Alexandra J.; Edwards, Jane C.; Hayes, Jack W. P.; Asfor, Amin S.; Owens, Raymond J.; Hammond, John A.; Gilbert, Sarah C.; Tuthill, Tobias J.

Clinical development of the COVID-19 vaccine candidate ChAdOx1 nCoV-19, a replication-deficient simian adenoviral vector expressing the full-length SARS-CoV-2 spike (S) protein was initiated in April 2020 following non-human primate studies using a single immunisation. Here, we compared the immunogenicity of one or two doses of ChAdOx1 nCoV-19 in both mice and pigs. Whilst a single dose induced antigen-specific antibody and T cells responses, a booster immunisation enhanced antibody responses, particularly in pigs, with a significant increase in SARS-CoV-2 neutralising titres.