PT  - JOURNAL ARTICLE
AU  - Alyssa Silva-Cayetano
AU  - William S. Foster
AU  - Silvia Innocentin
AU  - Sandra Belij-Rammerstorfer
AU  - Alexandra J. Spencer
AU  - Oliver T. Burton
AU  - Sigrid Fra-Bidó
AU  - Jia Le Lee
AU  - Nazia Thakur
AU  - Carina Conceicao
AU  - Daniel Wright
AU  - Jordan Barett
AU  - Nicola Evans-Bailey
AU  - Carly Noble
AU  - Dalan Bailey
AU  - Adrian Liston
AU  - Sarah C. Gilbert
AU  - Teresa Lambe
AU  - Michelle A. Linterman
TI  - A booster dose enhances immunogenicity of the COVID-19 vaccine candidate ChAdOx1 nCoV-19 in aged mice
AID  - 10.1101/2020.10.27.357426
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.10.27.357426
4099  - http://biorxiv.org/content/early/2020/10/27/2020.10.27.357426.short
4100  - http://biorxiv.org/content/early/2020/10/27/2020.10.27.357426.full
AB  - The spread of SARS-CoV-2 has caused a global pandemic that has affected almost every aspect of human life. The development of an effective COVID-19 vaccine could limit the morbidity and mortality caused by infection, and may enable the relaxation of social distancing measures. Age is one of the most significant risk factors for poor health outcomes after SARS-CoV-2 infection, therefore it is desirable that any new vaccine candidates should elicit a robust immune response in older adults. Here, we test the immunogenicity of the adenoviral vectored vaccine ChAdOx1 nCoV-19 (AZD-1222) in aged mice. We find that a single dose of this vaccine induces cellular and humoral immunity in aged mice, but at a reduced magnitude than in younger adult mice. Furthermore, we report that a second dose enhances the immune response to this vaccine in aged mice, indicating that a primeboost strategy may be a rational approach to enhance immunogenicity in older persons.Competing Interest StatementSarah Gilbert and Teresa Lambe are named on a patent application covering ChAdOx1 nCoV-19. The remaining authors declare no competing interests. The funders played no role in the conceptualisation, design, data collection, analysis, decision to publish, or preparation of the manuscript.