By Jane Elliott
BBC News, health reporter
Looking at seven-year-old Joe Duffill now it is hard to believe that he was once a very quiet and solitary little boy.
Joe Duffill has now caught up with peers
Today he is outgoing and confident and his parents put the dramatic personality change down to his hearing aids, which he wears each day.
Joe was born with a severe, but undiagnosed hearing loss.
About 840 babies, like Joe, are born each year in England with hearing loss in both ears and 500 with a loss in one ear.
Problems spotted sooner
But a system gradually phased in to screen each child at birth was not introduced until 2001, a year after Joe was born.
Under the old system the health visitor checked hearing at about 10 months, but many children's problems were not picked up until the 18 month tests and some, like Joe, not until much later.
By this time many of the children had language and speech problems and had fallen behind their peers at school.
Now, as a result of the programme, hearing impairment and deafness is typically identified in children within four months of birth and the average time to hearing aid fitting is now under five months.
The NHS Newborn Screening Programme is currently celebrating its two millionth screened child in England and more than 3,400 babies have now been identified as having permanent hearing impairment or deafness.
Joe's mum Suzanne said she wished the screening, which is also available in the rest of the UK, had been available for her son.
"If we had this hearing test his problems would have probably been spotted. I think these tests are such a good idea."
Suzanne, a student nurse from Bridgend, Wales, said they were not unduly worried about Joe's progress as a baby, despite a history of later-onset hearing loss in the males of the family.
"He was a lot quieter than his older sister, but we just put that down to all children developing differently."
He passed his hearing test at 10 months, but at the age of one was still struggling to speak.
And when he started school at the age of three-and-a-half he was still unable to speak properly.
"He was still doing baby babble so we were referred to the audiologist," Suzanne recalls.
His tests took a year to confirm the level of his hearing problems and tests revealed he also had glue ear - where the Eustachian tubes at the back of the inner ear fill with fluid. He needed grommets (small drains) fitted to release the pressure.
But by the time he was four-and-a-half Joe had his hearing aids fitted and started to catch up with his classmates.
At first he needed extra support with reading, but now Suzanne said Joe has matched his peers.
Parents are offered a newborn hearing test
"Before he got the hearing aids he was very isolated and did not mix.
"But within six months of getting the hearing aids he was coming on in leaps and bounds.
"I could really see him change. He needed some speech therapy. His speech is now really good.
"He is really confident. He is the only one at the school with a hearing aid, but everyone is lovely and if he can't hear what someone has said he is now confident enough to ask them to repeat it."
The only thing Joe has a problem with is hearing on the telephone, but his parents plan to get him a special one when he is older.
Professor Adrian Davis, programme director of the NHS Newborn Hearing Screening Programme, who called the two millionth screening "one of the biggest achievements in children's audiology over the last 40 years", said the new test meant more children getting their hearing losses spotted and treated earlier.
"Deafness and hearing impairment can have a major impact on a child's communication skills and development.
"Early identification, as a result of the programme, gives these babies better prospects of developing those essential skills. It also gives more opportunity for babies to bond within the family and experience social and emotional interaction from an early age," he said.
Health Minister Ivan Lewis said: "The programme has made a huge impact with babies being identified with a hearing loss on average one, if not sometimes, two years earlier than before, providing the potential to bring about an incredible change for these children and their families."
Angela King, audiologist for the RNID, said the new screening test meant most children have full diagnosis of hearing loss within a few months of birth.
"The screening is just that. It points out whether there is a problem and whether further tests are needed."
But she added that children and adults can develop hearing loss at any time, so it should be regularly monitored.