Vaccines contain a weakened form or small part of the bacterium or a virus that causes a disease, or tiny amounts of the chemicals that the bacterium produces. Vaccines work by causing the body’s immune system to develop memory to that infection. If your child comes into contact with the infection, the body will recognise it and can rapidly make antibodies (substances that fight off infection and disease) to protect him or her. Because vaccines have been used so successfully in the UK, diseases such as diphtheria have almost disappeared from this country. 

Find out more - How do vaccines work? (who.int)

Each vaccine will be made up of slightly different ingredients depending on how the vaccine has been developed. The active ingredient in a vaccine is a very small amount of a harmless form of the bacteria or virus you are vaccinating against, which cannot cause disease. The role of the active ingredient is to deliver antigens to your immune system to generate a specific immune response.

Find out more about vaccine ingredients - Vaccine ingredients | Vaccine Knowledge Project (ox.ac.uk)

Yes. From birth, babies’ immune systems protect them from the germs that surround them. Without this protection, babies would not be able to cope with the tens of thousands of bacteria and viruses that cover their skin, nose, throat and intestines. This protection carries on throughout life.

Studies have shown that it is safe to have several vaccinations at the same time and your baby will be protected as soon as possible from some very serious infections.

Most immunisations have to be given more than once to prepare your child’s immunity, this allows the body to learn how to fight the disease or virus. A booster vaccine is a repeated dose given to boost the immune response against the bacteria or virus. Immunity against some bacterias and viruses can fade over time and further exposure to the vaccine is required to increase immunity to maintain strong protection for a longer time.

The immunisation schedule is continually monitored to ensure that the timing and type of vaccination is as beneficial to your child as possible. Improvements to the schedule may involve changing the recommended age a vaccine is given at, the number of doses required, or introducing a new vaccine combination. Following extensive research, trials and analysis, new vaccines will also be added to the schedule to increase the number of diseases that your child can be protected from.

The most important thing to remember is that any change to the immunisation schedule is there to help keep your child as safe as possible, by protecting them from more diseases and ensuring a vaccine is as effective as possible.

The immunisation schedule has been designed so that your child can be vaccinated as soon as possible, at a time when each vaccine will be the most effective.

It is important to vaccinate your child at the age advised to make sure that they are protected from an early age. Babies and young children are the most vulnerable to disease and the longer you wait to vaccinate your child, the greater the possibility of them catching the disease and becoming ill.

There is no other proven, effective way to immunise your child against infectious disease without experiencing the serious risk of that infection. Childhood infections can cause serious illness, hospitalisation and life-long disabilities. Vaccines teach your child’s immune system how to create antibodies that protect them from diseases. It's much safer for your child’s immune system to learn this through vaccination than by catching the diseases and treating them. Vaccines mean if your child comes into contact with the infection, the antibodies will recognise it and be ready to protect them.

In the UK, these diseases, such as measles, are kept at bay by high immunisation rates. Around the world, millions of people a year die from infectious diseases with more than 5 million of these being children under the age of 5. Many of these deaths could be prevented by immunisation.

As more people travel abroad and more people come to visit this country, there is a risk that they will bring these diseases into the UK. The diseases may spread to people who haven’t been immunised, or who are still too young to be immunised. Immunisation doesn’t just protect your child; it also helps to protect your family and the whole community, especially those children who, for medical reasons, can’t be immunised. Refer to reasons why your baby should not be immunised for details .

Any side effects that occur are usually mild and short lived. Your child may get a little redness, swelling or tenderness where the injection was given that will disappear on its own. Fever can be expected after any vaccination. There is advice for parents on what to expect after vaccination here: What to expect after vaccinations.

Fever is more common after the first two doses of the Meningococcal B (Men B) vaccination, which are given at 8 weeks and 16 weeks old. There is specific advice for parents on how to prevent and treat fever after MenB vaccine at 8 and 16 weeks here: MenB vaccine and paracetamol

If your child has a minor illness without a fever, such as a cold, they should have their immunisations as normal. If your child is ill with a fever, put off the immunisation until the child has recovered. This is to avoid the fever being associated with the vaccine, or the vaccine increasing the fever your child already has.

No. Some years ago, there were stories suggesting a link between the MMR vaccine and autism. All medical authorities worldwide agree that no such link exists. Read more at MMR Vaccine (Measles, Mumps and Rubella Vaccine) | Vaccine Knowledge Project. 

Using single vaccines for the diseases would be experimental, and no country uses this approach. It’s unclear how long a gap to leave between each vaccine, as there’s limited evidence on giving all of these vaccines separately. Single vaccines are less safe than MMR because they leave children vulnerable to dangerous diseases for longer, and potentially increases the risk of allergic reactions. Giving 6 separate doses at spaced out intervals would mean that, after the first injection, the child still has no immunity to the other 2 diseases. No country recommends vaccination with the 3 separate vaccines. Some single vaccines are available in other European countries, where they may be used in special circumstances. For example, in France measles vaccine is used for nursery school children aged 9 to 12 months. These children usually have the MMR vaccine 6 months later.