A poll of 1,000 people across all five countries found that distrust in government was making respondents less eager for inoculation.
Just 43 per cent of people in Britain would “definitely” get the jab, with 32 per cent saying they “probably” would, Kantar found.
Only a third of Britons – 34 per cent – agree that, in general, vaccines are safe.
Trust in Covid vaccination has decreased in every country since June, with the US seeing the sharpest drop, researchers found.
The number of Americans saying they would “definitely” get vaccinated has fallen from 47 per cent in June to just 30 per cent at the end of last week.
The growing hesitation about the vaccine seems to be linked to the conditions under which it was developed and tested, the poll found.
Boris Johnson: Anti-vax is total nonsense, you should get a vaccine
In four of the five countries questioned, a majority of participants said they were worried about the safety of vaccines because of the speed with which they are developed and produced.
Only Germans showed less concern, at 41 per cent, while 69 per cent of French respondents expressed anxiety at the jabs’ development.
The survey’s results were published a day after health experts expressed their “joy” at the findings of the two leading vaccine trials.
Dr David Nabarro, a World Health Organisation (WHO) special envoy working on the pandemic, said news of Pfizer and Moderna’s successes proved science could triumph regardless of politics.
Dr Nabarro told the BBC on Monday that while people “might be a bit down in the mouth” about political issues, vaccine advances by scientists gave “everyone in the world to feel really good and warm about.”
“Every single person who has been working on this, we are only in it for one thing and that is to try and do the best we possibly can for the people of the world,” he said.
On Tuesday, Sir John Bell, regius professor of medicine at Oxford University, insisted vaccine developers had been meticulous in ensuring the safety of their candidates.
He told BBC Radio 4’s Today programme: “One always worries about side-effects from vaccines.”
But insisted that the jab manufacturers “have been pretty careful about thinking about safety during their trials.”
He added:“They’re all taking time to submit their applications for registration because they’re taking more time on the safety, to make sure that they’ve covered everything.
“You can never be complacent about safety but I think there’s a lot of effort going on.”
Sir John said he expected a mass-vaccination roll-out across the UK within the first half of next year.
“We can get vaccines into people in the UK and in most western countries pretty effectively,” he said.
“So I think the idea that we’re going to vaccinate a very large percentage of the population by spring is completely possible.
“And I think that will make a big difference because people will be then less anxious about catching the disease because they will be vaccinated, transmissions will fall to a low level and we may not be back completely to normal but things are going to look dramatically different by the spring.”
The Oxford University expert, who is a member of the Government’s vaccine taskforce, said he expected positive news from a number of other vaccine trials.
He explained: “It wasn’t certain until the Pfizer data came out last week that you could actually get a vaccine against this virus.”
But these results, along with those reported by Moderna, “makes it more likely – although not certain – that some of the other vaccines, including the Oxford/AstraZeneca vaccine, will have success in the coming weeks,” he said.
How does the Oxford vaccine differ to Pfizer’s?
Speaking to Times Radio, he acknowledged people were “tired and frustrated” by restrictive measures but said “compliance amongst members of the public is high”.
Mr Jenrick said recent vaccine developments were “good news” which “does give us all reason to believe that next year will be a much better picture than the one we’ve lived through in 2020”.
He added: “There should be doses of the Pfizer vaccine available to start vaccinating the most vulnerable in society before the end of this year and now that, coupled with the Moderna vaccine, means that tens of millions of our fellow citizens should be being vaccinated over the first half of next year.”