Dr Hans Kluge, European head of the World Health Organisation, said that although a possible jab might be available in the next 12 months, the best strategy to counter the spread of infection would remain “hand washing and distancing”.
He also raised concerns that not all countries would get the same access to a vaccine.
It comes after WHO director general Dr Tedros Adhanom Ghebreyesu said the spread of coronavirus was speeding up in many countries and the fight against the disease was far from over.
Speaking about the vaccine to the Daily Mail Dr Kluge said: “Everyone thinks that a vaccine is a panacea.
“First of all we don’t know if a vaccine will work in all age groups.
“Nobody knows [when there will be a vaccine]. My dream would be within a year. It’s possible but it’s also very possible it will not be in one year.
“But everyone talks about it as if it’s a silver bullet. But it’s absolutely not. I mean, 100 years ago we had Spanish flu and what was the best strategy? The same as now, hand washing and distancing.”
Dr Klunge, who oversees 53 countries in Europe including the UK, expressed concern over a “significant resurgence” of cases across the region,
He said Britain needed to improve its track and trace methods to help combat the disease.
The health chief also spoke of his fears of a second wave after seeing pictures of parties and mass gatherings in England.
“Please realise that we understand your fatigue but it’s not over,” he said.
“There is also a danger of getting ‘too confident’ over the summer before an ‘explosion’ of cases in the winter.”