Why vaccines are important

Vaccination is the most important thing we can do to protect ourselves and our children against ill health. They prevent millions of deaths worldwide every year.

Since vaccines were introduced in the UK, diseases like smallpox, polio and tetanus that used to kill or disable millions of people are either gone or are now very rarely seen.

Other diseases like measles and diphtheria have reduced to a very low number of cases each year since vaccines were introduced. These cases are often related to travel.

However, if people stop having vaccines, it's possible for infectious diseases to quickly spread again.

Measles and mumps in the UK

Measles and mumps are starting to appear again in UK, even though the MMR vaccine is the best protection against both diseases.

This is serious as measles can lead to life-threatening complications like meningitis, and mumps can cause hearing loss.

How vaccines work

Vaccines teach your immune system how to create antibodies that protect you from diseases.

It's much safer for your immune system to learn this through vaccination than by catching the diseases and treating them.

Once your immune system knows how to fight a disease, it can often give you life long protection.

Herd immunity

Having a vaccine also benefits your whole community through "herd immunity".

If enough people are vaccinated, it's harder for the disease to spread to those people who cannot have vaccines. For example, people who are ill or have a weakened immune system.

Vaccine safety

All vaccines are thoroughly tested to make sure they will not harm you or your child.

It often takes many years for a vaccine to make it through the trials and tests it needs to pass for approval.

Once a vaccine is being used in the UK it's also monitored for any rare side effects by the Medicines and Healthcare products Regulatory Agency (MHRA). It is also carefully monitored to make sure it still works.

Anyone can report a suspected side effect of vaccination to the MHRA through the Yellow Card Scheme.

Who cannot have vaccines

There are very few people who cannot have vaccines.

Generally, vaccines are only not suitable for:

• people who've had a serious allergic reaction (anaphylaxis) to a previous dose of the vaccine
• people who've had a serious allergic reaction to ingredients in the vaccine

People with weakened immune systems (for example, because of cancer treatment or a health condition) may also not be able to have some vaccines.

If you're not sure if you or your child can be vaccinated, check with a GP, practice nurse, health visitor or pharmacist.

Side effects of vaccination

Most of the side effects of vaccination are mild and do not last long.

The most common side effects of vaccination include:

• the area where the needle goes in looking red, swollen and feeling a bit sore for 2 to 3 days
• feeling a bit unwell or developing a high temperature for 1 or 2 days
• older children and adults may feel faint
• feeling tired, having a headache, mild fever, or flu-like symptoms

Some children might also cry and be upset immediately after the injection. This is normal and they should feel better after a cuddle. Common side effects usually pass after a few days.

Allergic reactions

It's rare for anyone to have a serious allergic reaction to a vaccination. If this does happen, it usually happens within minutes.

The person who vaccinates you or your child will be trained to deal with allergic reactions and treat them immediately. With prompt treatment, you or your child will make a good recovery.