FAQs

Vaccines help protect you against serious infectious diseases. They work by training your immune system to recognise and fight specific viruses or bacteria. Different vaccines work in slightly different ways. Some contain a very small, harmless part of a germ, while others provide instructions that help your body develop immunity.

Both types safely teach your immune system how to recognise and fight these germs. If you come into contact with the germ in the future, your immune system can respond more quickly. This can help prevent serious illness as your body fights the germ and to protect you from the disease and reduce severity of infection

Before vaccines were available, many children in the UK and around the world became seriously ill from diseases such as measles and meningitis. Some children died, and others were left with long-term health problems, including physical disabilities and learning difficulties. Vaccination helps protect children against these and many other serious diseases. It also helps prevent infections from spreading to other people, including babies, older adults, and those with weakened immune systems.

The World Health Organisation (WHO) estimates that vaccines save more than 4 million lives worldwide every year.

Natural immunity is the protection your child develops after having an infection. While this can provide immunity, the infection itself can sometimes cause serious illness and complications, which may lead to long-term health problems or, in rare cases, death. Vaccination is a safer way to help protect your child against a disease. It helps the immune system build protection without your child having to experience the infection and the risks associated with it.

Herd immunity works when a very high proportion of people in a community are vaccinated. This helps slow the spread of infectious diseases and provides some protection for people who are unable to be vaccinated. However, vaccination rates vary across the UK and between communities. If a disease such as measles is introduced into an area with lower vaccination rates, it can spread among children and adults who are not protected. If your child is not vaccinated, they may be at risk of becoming infected.

Some people, including very young babies and people with certain medical conditions or weakened immune systems, may not be able to receive some vaccines. They rely on others being vaccinated to help protect them from serious diseases. By vaccinating your child, you are helping to protect both your child and those around them.

No. During an outbreak, infectious diseases can spread quickly from person to person. People can sometimes pass on an infection before they feel ill, which means your child could be exposed to the disease before they are protected.

Vaccines do not provide protection immediately. It can take a few weeks for the body to build immunity after vaccination, and some vaccines require more than one dose for the best protection. If your child is vaccinated only after an outbreak has started, they may not have enough time to develop protection before being exposed to the disease. Therefore, it is important for your child to receive their vaccines according to the recommended schedule. If your child has missed any vaccinations, it is best to arrange them as soon as possible.

Sometimes a child may already have been exposed to an infection around the time they receive a vaccine. Because it can take some time for the body to build protection after vaccination, the vaccine may not have had enough time to work.

No vaccine is 100% effective, and some children may not develop as strong an immune response as others. However, if a vaccinated child does become infected, they are usually less likely to become seriously ill or develop severe complications than a child who has not been vaccinated.

Like all medicines, vaccines can cause side effects. Your child may have a sore arm where the injection was given, a mild fever, headache, tiredness, or a reduced appetite. Some children may also develop mild flu-like symptoms.

Most side effects are mild and short-lived, usually lasting 1 to 3 days. They are generally much less serious than the complications that can be caused by the diseases that vaccines help prevent.

Your child can usually still receive vaccines if they have a mild illness, such as a cold. If they have a high fever or feel very unwell, call your GP surgery for advice before their vaccination appointment.

Some children with weakened immune systems, including those receiving certain medical treatments, may need to delay some vaccines. Your GP or hospital specialist will advise you on which vaccines are suitable and explain when your child can be vaccinated.

Babies and children come into contact with millions of germs every day. The amount of material used in vaccines is very small compared with the number of germs that the immune system deals with naturally. The immune system can cope with this without difficulty.

Several vaccines are often given during the same appointment to help protect your child against as many serious diseases as possible at an early age. Some vaccines are combined into a single syringe, which reduces the number of injections your child needs. Combined vaccines are just as safe and effective as giving the vaccines separately.

Serious allergic reactions to vaccines are very rare. The healthcare professional giving the vaccine is trained to recognise and treat allergic reactions if they occur. If someone has a serious allergic reaction to a vaccine, they will usually be advised not to receive the same vaccine again.

Some vaccines contain very small amounts of ingredients, including traces of antibiotics such as neomycin, which may be used during the manufacturing process to prevent contamination. If your child has a known allergy to neomycin, or if you are concerned about any allergies, including allergies to medicines, foods or other substances, speak to your nurse, health visitor or GP before vaccination.

The MMR vaccine protects against measles, mumps and rubella. Since January 2026, the MMRV vaccine has been offered to some children and also protects against varicella (chickenpox). Some parents worry about a possible link between these vaccines and autism. It is understandable to have questions about this, especially when there is a lot of information online and on social media about it. However, extensive research involving large numbers of children in many countries has found no evidence that the MMR or MMRV vaccine causes autism. Studies comparing children who have received these vaccines with children who have not have shown that autism rates are similar in both groups. Some parents are also concerned about other vaccines and autism. Research has found no evidence that any routine childhood vaccine causes autism. Vaccination remains the safest and most effective way to protect children against serious infectious diseases.

The main ingredients in a vaccine are the active components that help train your immune system to recognise and fight an infection, together with water. Vaccines also contain small amounts of other ingredients that help keep them safe, effective and stable.

For example, a small amount of porcine gelatine is used in some vaccines to help keep them stable. In the UK childhood vaccination programme, this includes the flu nasal spray, MMR VaxPro and MMRV ProQuad vaccines. Porcine gelatine helps ensure these vaccines remain safe and effective. There are alternatives to all three vaccines that do not contain porcine gelatine. Please ask for these when making an appointment or when arriving at a catch-up clinic

Another example is aluminium salts, which are used in some vaccines to help the immune system respond more effectively. Aluminium is also found naturally in the environment and in many foods, drinking water, breast milk and infant formula. There is no evidence that the small amounts used in vaccines are harmful.

For information about vaccine ingredients, visit Oxford University’s Vaccine ingredients | Vaccine Knowledge Project

All vaccines have been carefully tested in clinical trials before being approved for use. These trials assess how safe and effective the vaccines are and involve thousands of people. Once a vaccine is in use, its safety continues to be monitored. In the UK, the Medicines and Healthcare products Regulatory Agency (MHRA) continuously monitors vaccines for any rare side effects and takes action if any safety concerns are identified. Anyone can report suspected side effects through the MHRA Yellow Card scheme website. This helps experts identify and investigate any possible safety issues.

Vaccines are given at different ages, and many require more than one dose. This helps your child’s immune system build strong and long-lasting protection against disease.

It is important to start vaccinations when your child is young because some infectious diseases can be particularly serious during infancy and early childhood.

Children under 4 usually receive their vaccines at their GP surgery. You will normally receive an invitation when a vaccine is due. However, if your child is due a vaccination, you can make an appointment, and you do not need to wait for the invitation.

Children aged 4 and over may receive some vaccinations at school from a trained vaccination team. The school will provide information about the vaccine and a consent form.

If your child has missed any vaccines, they can still catch up:

• At your GP surgery
• For the MMR vaccine and school-age vaccines, you can attend a catch-up clinic. In Enfield, these are organised by Vaccination UK. Your child does not need to be registered with a GP. For more information visit  Catch-up clinics | Enfield

Your child’s Personal Child Health Record (Red Book) contains a record of their vaccinations and shows when future vaccinations are due.