ChAdOx1 nCoV-19 vaccine induces immune response and is safe in humans, early trial data suggests

The University of Oxford’s ChAdOx1 nCoV-19 vaccine induces a strong immune response with no serious adverse reactions, preliminary findings of a phase I/II trial published in The Lancet (20 July 2020) have suggested^[1]
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Between 23 April 2020 and 21 May 2020, 1,077 healthy adults aged 18–55 years with no history of SARS-CoV-2 infection were randomly assigned to receive either ChAdOx1 nCoV-19 or the control, a meningococcal conjugate vaccine (MenACWY), as a single intramuscular injection.

Then, 28 days after the first vaccine, 10 participants in the ChAdOx1 nCoV-19 group were assigned to receive a second dose of the vaccine.

ChAdOx1 nCoV-19 was found to be safe and tolerated with no serious adverse reactions. The majority of adverse events reported were mild or moderate, and most could be managed with paracetamol.

In the ChAdOx1 nCoV-19 group, T-cell responses peaked 14 days after vaccination; antibody responses rose by day 28 and were boosted following a second dose of the vaccine. Neutralising antibody responses against the SARS-CoV-2 virus were detected in all participants after a second vaccine dose.

“These encouraging results support further evaluation of this candidate vaccine in our ongoing large scale phase III programme, which is still needed to assess the ability of the vaccine to protect people from COVID-19,” said Sarah Gilbert, professor of vaccinology at the University of Oxford Jenner Institute and co-author of the study.