The popular Coronation Street actress, who portrays barmaid Betty Williams on the ITV1 soap, was admitted to an undisclosed Greater Manchester hospital last week with symptoms of pneumonia.
The Sun quotes a friend of Driver as saying: "[Betty] is being kept in for observation. She's in good spirits."
A report late last week said that Driver was "in good spirits" as she received continued treatment.
William Roache, who plays Ken Barlow on the show, told BBC News at this weekend's British Soap Awards that the actress was "coming along fine" but would remain in hospital.
Driver made her first appearance on the soap in 1969 and was the subject of a major career retrospective on ITV1 earlier this year.
She will mark her birthday this Friday, May 20.
> Betty Driver: 'Documentary was my idea'