Children will get a new combined jab

Health officials said it will protect against diphtheria, tetanus, whooping cough and polio in a single injection.

Concerns were raised in the US about a mercury-based preservative in whooping cough vaccine.

The new vaccine will not include a mercury preservative but officials said its removal was not due to safety concerns.

Possible contamination

The five-in-one is a replacement for an immunisation schedule which is currently four-in-one, plus oral polio drops.

It is to be given to infants at two, three and four months, with boosters for pre-school children and teenagers.

The new "inactivated" polio vaccination will replace the oral polio vaccine in an attempt to avoid possible polio contamination.

The move comes just weeks after researchers in the US suggested that the mercury-based preservative thiomersal used in current whooping cough vaccine could be linked to the development of autism.

Health officials agreed that mercury should be removed from the whooping cough vaccine following the research.

This is a pure public health measure which is being taken in the interests of children Dr Mac Armstrong Chief medical officer

However, the Department of Health has always maintained there is no evidence of such a link.

Campaigners against multiple vaccines have expressed concern over the safety of the new combined dose.

They have warned of a repeat of the MMR controversy unless more safety assurances are given about the implications of the new jab.

Some parents who believe their children were harmed by the MMR jab have said they were "extremely worried" at the prospect of a new combined vaccination.

However, the executive said it is safe and has been thoroughly tested.

Bill Welsh, chairman of the campaign group Action Against Autism, said he believes the real motive for the introduction of a new vaccination is money.

He said: "It is important that we try and address the problem of childhood diseases but I think that, by combining vaccines, it has been taken one step too far.

"I believe that this vaccination program is deeply flawed, I believe that it is profit driven, cost driven and I believe that the medical hierarchy have allowed themselves to be contaminated by that profit motive."

Mercury-free

Scotland's chief medical officer, Dr Mac Armstrong, described Mr Welsh's claims as "extraordinary."

Speaking to BBC Radio Scotland, he said: "This is a pure public health measure which is being taken in the interests of children.

"We have immunised children against these five diseases, all at the same time, for years.

"This five-in-one is a replacement for an immunisation schedule which is currently four-in-one, plus oral drops. "

He added: "A big advantage of the new vaccine, which is just as effective as the old one, is that we can now make it mercury-free.

"We know parents have been concerned [about mercury] and we've been saying for the last couple of years that - in line with governments throughout the world - we would take all possible steps to remove mercury from vaccines as soon as it was possible to do so.

"There is no risk with the current vaccine, but we know parents are concerned about it.

"Mercury is there in a very low level as a preservative, but the new generation of vaccines don't need a preservative so we are willing to remove it as soon as we possibly can."

Dr Armstrong confirmed that GPs will be able to offer the vaccines from next month.

He said: "GPs will start using the new vaccines as soon as they become available from September and patients will continue to be called for appointments as part of the childhood immunisation programme.