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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 20191,2 and is responsible for the coronavirus disease 2019 (COVID-19) pandemic3. Vaccines are an essential countermeasure and are urgently needed to control the pandemic4. Here we show that the adenovirus-vector-based vaccine ChAdOx1 nCoV-19, which encodes the spike protein of SARS-CoV-2, is immunogenic in mice and elicites a robust humoral and cell-mediated response. This response was predominantly mediated by type-1 T helper cells, as demonstrated by the profiling of the IgG subclass and the expression of cytokines. Vaccination with ChAdOx1 nCoV-19 (using either a prime-only or a prime-boost regimen) induced a balanced humoral and cellular immune response of type-1 and type-2 T helper cells in rhesus macaques. We observed a significantly reduced viral load in the bronchoalveolar lavage fluid and lower respiratory tract tissue of vaccinated rhesus macaques that were challenged with SARS-CoV-2 compared with control animals, and no pneumonia was observed in vaccinated SARS-CoV-2-infected animals. However, there was no difference in nasal shedding between vaccinated and control SARS-CoV-2-infected macaques. Notably, we found no evidence of immune-enhanced disease after viral challenge in vaccinated SARS-CoV-2-infected animals. The safety, immunogenicity and efficacy profiles of ChAdOx1 nCoV-19 against symptomatic PCR-positive COVID-19 disease will now be assessed in randomized controlled clinical trials in humans.

Original publication

DOI

10.1038/s41586-020-2608-y

Type

Journal article

Journal

Nature

Publication Date

10/2020

Volume

586

Pages

578 - 582

Keywords

Adenoviridae, Animals, Betacoronavirus, Bronchoalveolar Lavage Fluid, COVID-19, COVID-19 Vaccines, Coronavirus Infections, Cytokines, Disease Models, Animal, Female, Immunity, Cellular, Immunity, Humoral, Immunoglobulin G, Lung, Macaca mulatta, Male, Mice, Pandemics, Pneumonia, Viral, SARS-CoV-2, Spike Glycoprotein, Coronavirus, Th1 Cells, Vaccination, Viral Load, Viral Vaccines