Child health experts have dismissed safety fears surrounding the new five-in-one vaccine for babies.

Child health experts have dismissed safety fears surrounding the new five-in-one vaccine for babies.

The conventional four-in-one vaccine is to be replaced next month with a jab that provides immunisation against diphtheria, tetanus, whooping cough, Hib (influenza B) and polio.

The announcement sparked concern among some parents and an outcry among campaigners who claimed that the new jab could "overload" the immune system.

Yesterday, two specialists dismissed the fears as unfounded in an editorial in the British Medical Journal.

Helen Bedford, from the Institute of Child Health in London, and David Elliman, a consultant in community child health at Great Ormond Street hospital, welcomed the new jab as in important development for child vaccines and an improvement on the original formula.

Amid fears that the new jab could spark a damaging health scare similar to that surrounding the MMR vaccine, the two specialists also described the public panic as "regrettable", saying it offered a better formulation of vaccinations.

In the new format jab, the "whole cell" vaccine for whooping cough is to be replaced with a new "acellular" vaccine, in order to reduce side-effects.

An inactivated vaccine will also replace the live oral polio vaccine, which carries a very small risk of causing paralytic polio, because the risk of the disease being imported is now so small.

The two specialists said new research into the pediacel - the new five-in-one jab - has proved that it has noticeably fewer side-effects in comparison with the current jab.

The findings of the clinical trials, which are to be published later this year, should reassure parents concerned about the furore over the jabs, according to the specialists.

"This should prove popular with parents who in one study said that they would prefer a vaccine that causes fewer reactions, even if this meant having an additional injection to offset this problem," they said.

Claims that the combined jab would result in overloading the immune system of babies were also dismissed as incorrect. "This is based on two misconceptions," they said. "One is that the immune system has a limited and relatively small capacity that is pushed to the limits by multiple vaccines.

"The other is that the increase in the number of diseases being protected against means an increase in the number of antigens."

However, the authors highlighted that the new vaccine had around 3,000 fewer antigens than the one it was replacing, despite the fact it was protecting against five diseases.

While the pair hailed the new jab as an important step forward in the UK's vaccination programme, they urged parents not to delay immunisation until after its introduction.

"The benefits of the new vaccine do not outweigh the risks of delaying immunisation until its introduction," they said.

"Such a delay would leave a child unnecessarily at risk of death and disability from whooping cough and Hib disease.

"Parents should therefore be encouraged to have their children immunised according to the current schedule, until the new one is introduced."