Scientists and medical researchers across the UK have welcomed the "very encouraging" results from the University of Oxford's coronavirus vaccine trials.
The speed at which the trial has been conducted has also been praised, with the preliminary results suggesting the vaccine is safe and causes few side effects.
Although results of the first phases of the trial in humans show it is safe and induces an immune response in the laboratory, there is a long way to go.
The study has not yet shown whether the vaccine can prevent infection.
Professor Fiona Watt, executive chairwoman of the Medical Research Council, which helped to fund the trial, said: "It is truly remarkable how fast this vaccine has progressed, with our support, through early clinical trials, and it is very encouraging that it shows no safety concerns and evokes strong immune responses.
"There is a lot that we don't yet know about immunity to the virus that causes Covid-19.
"However, it seems that both antibody and T cell immunity are important, and this vaccine triggers both responses.
"The much anticipated next milestone will be the results of the larger trials that are happening now to find out if the vaccine will protect people from the virus."
Despite the positive results many also acknowledge there is still "a long way to go" before the vaccine can be rolled out for general use.
Professor Jonathan Ball, professor of molecular virology, University of Nottingham, said: "The results of the Oxford chimp adenovirus vaccine candidate show that the vaccine is able to generate antibodies and T cells in humans and these persisted for several weeks. Whilst encouraging there is still a long way to go before we can herald the arrival of a successful coronavirus vaccine."
Professor Ian Jones, professor of virology, University of Reading, added that the trial data was "as good as one could reasonably expect".
Health research charity Wellcome Trust praised the early success of the university's research but said that more than one vaccine would likely be necessary to fight the virus on a global scale.
Alex Harris, head of Global Policy & Advocacy at Wellcome, said: "This is just one crucial step but it's very encouraging, and builds on the incredible global research effort during this crisis.
"To see promising results from several candidates in months is remarkable, but we must also be prepared for some candidates to fail in the later stages and be realistic about time-frames for manufacturing and rollout."
The government has signed deals for 90m doses of promising Covid-19 vaccines, with more in the pipeline.
The latest deal is for vaccines being developed by an alliance between the pharmaceutical giants BioNtech and Pfizer as well as the firm Valneva.
This is in addition to 100m doses of the vaccine being developed by Oxford University with AstraZeneca. Kate Bingham, chairwoman of the UK Vaccine Taskforce, said she is hopeful of a vaccine by the end of the year.