Up to half of the populations in countries including the United States, Germany and the Czech Republic say they may not get any new coronavirus vaccine that is developed.
A vaccine against the deadly virus that has swept the globe over the last six months is seen as possibly the only way for the world to return to normal after the pandemic, and scientists in hundreds of different countries are working as fast as they can to try to produce one.
However, experts have estimated that at least 70 per cent of people will have to get the vaccine in order for it to stop coronavirus, a figure that appears to be some way off based on the latest numbers.
Professor Heidi Larson, anthropologist and director of the Vaccine Confidence Project at the London School of Hygiene and Tropical Medicine, said: "It's going to be a challenge, particularly because in general, populations are more anxious about new vaccines and that's understandable.
"But the good news is we do have time before we, hopefully, get a vaccine, so I think that we have to use that."
In the United States, a number of polls have shown that only around 50 per cent are committed to getting a coronavirus vaccine.
This week, the country's leading public health expert Dr Anthony Fauci told CNN he believed that the US was "unlikely" to reach herd immunity as a result of this, inspired by the "general anti-science, anti-authority, anti-vaccine feeling".
In Germany, a poll this week by YouGov found that only one in two Germans would definitely get vaccinated if there was a jab available, and one in five said they definitely would not. A protest was held in Ukraine on Friday over the potential for compulsory coronavirus vaccinations.
The picture is similar in many different nations, and has been linked in part to the growing influence of the so-called anti-vaxxer movements, whose efforts persuading parents not to immunise their children against diseases like measles have caused major outbreaks in the last two years in countries including the the United States, the United Kingdom and the Czech Republic, where the illness was thought to have been eliminated.
Dr. Jiří Černý, a leading virologist at the Faculty of Tropical AgriSciences at the Czech University of Life Sciences in Prague, the Czech Republic - where recent research found that only 49 per cent of people would take a coronavirus vaccine - said mandatory vaccination should be considered.
"It is probable that even if a high quality vaccine is available, the number of people who get voluntarily vaccinated in Czechia will be rather low, which is not sufficient to develop herd immunity," he warned.
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