The medic, who was awarded an MBE at the Queen's latest round of honours, said that there is a glimmer of hope amid the coronavirus pandemic as England gets ready to go into lockdown.
Offering a more positive outlook than in recent months, Dr Hilary, who also appears on Good Morning Britain, explained how it is possible to see a vaccine being released before the end of the year.
Dr Hilary said: "It could be rolled out within the next four weeks. So even before Christmas.
"The priority would be to those over 85 and frontline key workers.
"Then it would go care home workers, residents and heath visitors."
Nodding, Lorraine added: "So the really important people."
Hilary continued: "Yes, and the most vulnerable first and then over time everyone else."
Explaining how the potential vaccine will be rolled out, he added: "They are thinking that GPs will be prepared to do this along with other trained staff who don't usually give vaccines in lots of different centres.
"It's a ray of hope and something that we have been looking for for a long time."
Beaming, Lorraine replied: "It really is. As you say it could be a game changer."
Speaking on Wednesday morning on the BBC Radio 4's Today's Programme, NHS England's chief executive Sir Simon Stevens said: "There are over 200 vaccines in development and we believe that we should hopefully get one or more of those available from the first part of next year.
"In anticipation of that we're also gearing the NHS up to be ready to make a start on administering COVID-19 vaccines before Christmas, if they become available."
On Wednesday's evening, UK MP's are set to vote in the House of Commons to send the UK into a month-long lockdown.
Prime Minister Boris Johnson has said the lockdown would last until December 2 in a bid to bring down the R rate across the country.
Lorraine airs weekdays on ITV at 9am