A coronavirus vaccine being developed at the University of Oxford is safe and induces an immune reaction, findings of the first phases of the study suggest.
The findings on the Oxford vaccine trial were published in medical journal, The Lancet on Monday.
It says: "Our preliminary findings show that the candidate ChAdOx1 nCoV-19 vaccine given as a single dose was safe and tolerated."
No serious adverse reactions to ChAdOx1 nCoV-19 occurred. The majority of adverse events reported were mild or moderate in severity, and all were self-limiting.
The study showed that a single dose of ChAdOx1 nCoV-19 elicits an increase in spike-specific antibodies by day 28 and neutralising antibody in all participants after a booster dose.
High levels of neutralising antibody at baseline seen in a small number of participants probably indicates prior asymptomatic infection, as potential participants with recent Covid-19-like symptoms or with a history of positive test for SARS-CoV-2 were excluded from the study.
Limitations of this study include the short follow-up reported to date, the small number of participants in the prime-boost group, and single-blinded design, although staff undertaking clinical evaluation and laboratory staff all remained blinded.
Additionally, the study findings are not easily generalisable, as this is a first-in-human study of fairly young and healthy volunteers, the majority of whom were white.
Further studies are required to assess the vaccine in various population groups including older age groups, those with co-morbidities, and in ethnically and geographically diverse populations.
Professor Sarah Gilbert, of the University of Oxford, said: “There is still much work to be done before we can confirm if our vaccine will help manage the Covid-19 pandemic, but these early results hold promise.
“As well as continuing to test our vaccine in phase-three trials, we need to learn more about the virus – for example, we still do not know how strong an immune response we need to provoke to effectively protect against Sars-Cov-2 infection.
“If our vaccine is effective, it is a promising option as these types of vaccine can be manufactured at large scale.
“A successful vaccine against Sars-Cov-2 could be used to prevent infection, disease and death in the whole population, with high-risk populations such as hospital workers and older adults prioritised to receive vaccination.”
Earlier, the UK boss of the pharmaceutical company Pfizer, Ben Osborn, expressed his hope that a vaccine against coronavirus which it is developing could be ready as "early as October" subject to checks that it is safe and effective.
And Prime Minister Boris Johnson was relatively downbeat when he said on Monday that a vaccine may not even be ready by the end of this year or next.
He said he had his "fingers crossed" a vaccine will be found but said he couldn't be 100 per cent confident.
Separately, agreement has been reached for 30 million doses of coronavirus vaccine from German firm BioNTech and the US company Pfizer, and 60 million doses from France's Valneva.
The figure is in addition to the 100 million doses of vaccine that are being developed by Oxford University in partnership with AstraZeneca, as well as another at Imperial College London which started human trials of its vaccine in June.
Health Secretary Matt Hancock said the update on the vaccine was “very encouraging news”.
He tweeted: “We have already ordered 100 million doses of this vaccine, should it succeed."
He congratulated the scientists and the leadership of Astra Zeneca.
