Despite renewed appeals from politicians and a host of pop-up vaccination centres across the country, the latest national statistics suggest a hesitancy among some people aged between 18 and 29.
Professor Adam Finn, member of the Joint Committee on Vaccination and Immunisation, believes many younger people think they are safe from the virus despite a recent surge in Covid hospital admissions, and warned people "not to die of ignorance".
NHS England data shows in Doncaster, 29,714 people aged between 18 and 29 had received a first dose of a vaccine by August 7 – at least 63 per cent of the age group, based on the number of people on the National Immunisation Management Service.
It meant around 37 per cent of this cohort were yet to receive a jab at that point, compared to 19 per cent among adults of all ages.
Across Yorkshire and The Humber as a whole, 38 per cent of people aged between 18 and 29 had not received a first jab by August 7.
All adults in England have been able to book a first vaccine dose since June 17.
The low vaccination rate among younger people comes amid a warning from NHS England that more than a fifth of those currently being admitted to hospital with Covid-19 are aged between 18 and 34 – a figure that is four times higher than the peak last winter.
Chief executive Amanda Pritchard said vaccines had a "major impact" in keeping people out of hospital and saving lives.
Prof Finn, who advises the Government on the vaccine programme, said he sensed a perception among many young adults that they are not at risk from the virus, unlike those from older age groups.
He said: "We are now seeing people who are young and previously healthy getting seriously ill, so it would be correct to adjust that perception.
"It is important not to die of ignorance – if you really know the facts about the disease and know the facts about vaccinations, going and getting the vaccination is a complete no-brainer."
Efforts by the Government to get young adults to come forward for a first jab include plans for a Covid vaccine passport that would make full vaccination a requirement for entry to nightclubs and other venues from the end of September.
Pop-up vaccine centres also opened across the country recently, while food delivery company Deliveroo and taxi firm Uber have both been enlisted to offer discounted meals and rides for customers if they get a jab.
Prof Finn said some of the incentives were "carrot and stick" ideas and warned forcing people into receiving a vaccination could have adverse consequences.
"In the end, vaccines are good things and something people should want and accept," he said.
The Government said it was working to provide information and advice "at every opportunity" to drive vaccine uptake among young people.
Vaccines Minister Nadhim Zahawi said: "Getting both doses of the jab is the most important thing you can do to protect yourself and avoid unknowingly passing the virus on to someone who may be more vulnerable to Covid-19."