ChAdOx1 nCoV-19 vaccination prevents SARS-CoV-2 pneumonia in rhesus macaques
van Doremalen N., Lambe T., Spencer A., Belij-Rammerstorfer S., Purushotham JN., Port JR., Avanzato V., Bushmaker T., Flaxman A., Ulaszewska M., Feldmann F., Allen ER., Sharpe H., Schulz J., Holbrook M., Okumura A., Meade-White K., Pérez-Pérez L., Bissett C., Gilbride C., Williamson BN., Rosenke R., Long D., Ishwarbhai A., Kailath R., Rose L., Morris S., Powers C., Lovaglio J., Hanley PW., Scott D., Saturday G., de Wit E., Gilbert SC., Munster VJ.
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) emerged in December 20191,2 and is responsible for the COVID-19 pandemic3. Vaccines are an essential countermeasure urgently needed to control the pandemic4. Here, we show that the adenovirus-vectored vaccine ChAdOx1 nCoV-19, encoding the spike protein of SARS-CoV-2, is immunogenic in mice, eliciting a robust humoral and cell-mediated response. This response was not Th2 dominated, as demonstrated by IgG subclass and cytokine expression profiling. A single vaccination with ChAdOx1 nCoV-19 induced a humoral and cellular immune response in rhesus macaques. We observed a significantly reduced viral load in bronchoalveolar lavage fluid and respiratory tract tissue of vaccinated animals challenged with SARS-CoV-2 compared with control animals, and no pneumonia was observed in vaccinated rhesus macaques. Importantly, no evidence of immune-enhanced disease following viral challenge in vaccinated animals was observed. ChAdOx1 nCoV-19 is currently under investigation in a phase I clinical trial. Safety, immunogenicity and efficacy against symptomatic PCR-positive COVID-19 disease will now be assessed in randomised controlled human clinical trials.