If one is ready by autumn, it would likely only be available in very limited numbers for priority recipients, with a mass roll-out even early next year considered "an incredibly good and fast result", experts added.
The reaction comes after a claim by an Oxford professor that she is "80%" confident of the success of a vaccine she and her colleagues are working on.
Sarah Gilbert, a professor of vaccinology at Oxford University, is leading a team of researchers in the development of a vaccine that would protect the world against coronavirus.
In an interview with The Times, the professor said they have already created a potential vaccine that is due to begin human trials within two weeks.
It is understood that developing a vaccine within a year to 18 months would be considered unbelievably fast by Government scientists and that having one available for use across the world by the middle of next year would be seen as a remarkable achievement.
Prof Gilbert said the autumn timeframe is "just about possible if everything goes perfectly".
She explained the team is planning studies worldwide, where lockdowns are at different stages, in the hope that that could accelerate the clinical trial process.
"If one of those (places) turns out to have a high rate of virus transmission then we will get our efficacy results very quickly, so that is one strategy for reducing the time," she said.
In order for the vaccine to be distributed in the autumn, Prof Gilbert says the Government will need to start production before it is proven to work.
While not commenting directly on this particular trial, the Department of Health has said if vaccines currently under development in the UK prove to be safe and effective in clinical trials, there are a number of manufacturing and supply chain options available to meet the projected demands.
The Government has said in order to put the UK in a position to accelerate vaccine development and manufacture, it is bringing together a wide range of sectors, including industry, academics, funding agencies, regulators, logistics and finance.
Both Professor Stephen Evans, from the London School of Hygiene and Tropical Medicine, and Dr Colin Butter, associate professor and programme leader in bioveterinary science at the University of Lincoln, said they would treat news of a possible vaccine with "cautious optimism".
Prof Evans, who commended Prof Gilbert for being careful to make clear there are no guarantees, said having the vaccine ready and proven to be safe is one thing, but availability in the millions of doses required for large-scale rollout across the UK with a system for delivery is a different matter.
The expert in the safety of medicines and vaccines, said: "Cautious optimism is entirely justified in these difficult times but if you think that that's it, then you could be sorely disappointed. There are numbers of hurdles to overcome before you get to the point where the population is protected."
Dr Butter, a flu biologist who has previously worked with Prof Gilbert on vaccines for avian flu, said it is important to understand there will not be "60-odd million doses" by September to vaccinate the entire population of the UK.
"Having it available in September means the safety and efficacy would be understood and there would be a limited amount of vaccine available for distribution," he said.
Key workers and vulnerable people would likely take a higher priority in the queue for vaccines, he added.
Editor’s note: first and foremost - and rarely have I written down these words with more sincerity - I hope this finds you well.
Almost certainly you are here because you value the quality and the integrity of the journalism produced by The Yorkshire Post’s journalists - almost all of which live alongside you in Yorkshire, spending the wages they earn with Yorkshire businesses - who last year took this title to the industry watchdog’s Most Trusted Newspaper in Britain accolade.
And that is why I must make an urgent request of you: as advertising revenue declines, your support becomes evermore crucial to the maintenance of the journalistic standards expected of The Yorkshire Post. If you can, safely, please buy a paper or take up a subscription. We want to continue to make you proud of Yorkshire’s National Newspaper but we are going to need your help.
Postal subscription copies can be ordered by calling 0330 4030066 or by emailing [email protected] Vouchers, to be exchanged at retail sales outlets - our newsagents need you, too - can be subscribed to by contacting subscriptions on 0330 1235950 or by visiting www.localsubsplus.co.uk where you should select The Yorkshire Post from the list of titles available.
If you want to help right now, download our tablet app from the App / Play Stores. Every contribution you make helps to provide this county with the best regional journalism in the country.
Sincerely. Thank you.