How the injections compare

All babies are currently offered vaccines against diphtheria, tetanus, whooping cough, Hib and polio.

The injection for diphtheria, tetanus, whooping cough and Hib is known as DTwP. Polio is given orally.

Until now, most children have received it in stages, at the age of two, three and four months.

Under the new plans, the polio vaccine will be added to the DTwP jab - creating a five-in-one injection.

It will still be administered at two, three and four months. The changes have two main aims. The first is to replace the existing polio regime with a safer form of vaccine. The traditional polio vaccine was "live" - creating a tiny risk that children could contract the disease from the injection.

The second aim is to refine the vaccine protecting children from whooping cough. There are fears that a mercury-based preservative in the vaccine could trigger autism.

Health chiefs say they do not believe this to be the case but are anxious to avoid criticism that they are taking any unnecessary risks.