Why vaccination is important
Vaccines are the most effective way to prevent many infectious diseases. This page explains how vaccines work, what they contain and the most common side effects.
Be aware of anti-vaccine stories
Anti-vaccine stories are often spread online through social media and offline.
Always get your vaccine and health information from trusted sources, such as the NHS or World Health Organisation (WHO).
The vaccine information on social media may not be based on scientific evidence and could put your child at risk of a serious illness.
All the current evidence tells us that getting vaccinated is safer than not getting vaccinated.
Things you need to know about vaccines
Vaccines do
- help to protect you and your child from many serious and potentially deadly diseases
- protect other people in your family and community – by helping to stop diseases spreading to people who cannot have vaccines, such as babies too young to be vaccinated and those who are too ill to be vaccinated
- undergo rigorous safety testing before being introduced – they're also constantly monitored for side effects after being introduced
- sometimes cause mild side effects that will not last long – you may feel a bit unwell and have a sore arm for 2 or 3 days
- reduce or even get rid of some diseases – if enough people are vaccinated
Vaccines do not
- do not overload or weaken the immune system – it's safe to give children and adults several vaccines at a time and this reduces the amount of injections needed
- do not contain mercury (thiomersal)
- do not contain any ingredients that cause harm – only ingredients essential to making them safer and more effective and only in very small amounts
- do not cause autism – studies have found no evidence of a link between the MMR vaccine and autism
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.
Information:
The World Health Organization (WHO) has listed vaccine hesitancy as one of the biggest threats to global health.
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.
Important
If 95% of children receive the MMR vaccine, this would stop measles spreading completely.
However, measles, mumps and rubella can quickly spread again if fewer than 90% of people are vaccinated.
Everyone should be up to date with their routine vaccinations to give them the best protection.
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.
Non-urgent advice: Speak to your GP or practice nurse if:
- you're worried about you or your child having a vaccine
- you're not sure if you or your child can have a vaccine
You could also ask a health visitor any questions you have about vaccines.
What's in a vaccine?
Most vaccines contain a small amount of bacteria, virus or toxin that's been weakened or destroyed in a laboratory first.
Some contain chemicals that make your body think it's coming into contact with the bacteria, virus or toxin.
This means there's a very low risk of healthy people catching a disease from a vaccine. It's also why you might see vaccines being called "live" or "non-live".
Differences between live and non-live vaccines
Live (weakened) vaccines
- Contain viruses or bacteria that have been weakened
- Cannot be given to people with a weakened immune system
- Gives long-term protection
Non-live (destroyed) vaccines
- Contain viruses or bacteria that have been destroyed
- Can still be given to people with a weakened immune system
- Often needs several doses or a booster vaccine for full protection
Other vaccine ingredients
Vaccines contain other ingredients that help make the vaccine more effective.
The main ingredient in vaccines is water. The other ingredients are used in very small amounts.
There is no evidence that any of the ingredients are harmful in such small amounts.
A full list of any vaccine's ingredients is available on the electronic medicines compendium (emc) website
Read more about specific vaccine ingredients on the Oxford University Vaccine Knowledge Project website
Last Updated: 01/01/0001 00:00:00
The information on this page has been adapted by NHS Wales from original content supplied by
NHS website
nhs.uk