With the winter months very much underway, and the seasonal sniffles doing the rounds, now seems like a better time than ever to talk about vaccinations.
And in a world where the “anti-vax” movement has become more visible and misinformation spreads quickly online, revisiting the basics is more important than ever.
Childhood vaccination schedules aren’t arbitrary, rushed, or designed for convenience. They are based on decades of research into how a child’s immune system develops, when certain infections pose the greatest risk, and how best to offer safe, long-lasting protection.
This article explores the science behind the schedule, why timely vaccination matters, and what parents need to know to make confident, informed decisions about their child’s health.
Contents
- What Are Vaccines, and How Do They Work?
- Why We Vaccinate When We Do
- Understanding The Role of Herd Immunity
- What Do We Vaccinate Against and Why?
- What Are The Risks of Vaccinating Children?
- In Summary
- Childhood Vaccination Schedule 2025
DISCLAIMER:
While I am a practising doctor, the information on this site is for educational purposes only. It does not take into account your personal circumstances, which can significantly affect medical decision-making and treatment. This content therefore does not constitute medical advice, and should not be relied upon for diagnosis or treatment. Always consult a qualified healthcare provider regarding any health concerns.
This article was written on the 24/11/2025 using up-to-date sources at that time. Please be aware that medical information and guidelines change often.
What Are Vaccines, and How Do They Work?
Germs – or pathogens – are all around us, and when we come into contact with these pathogens, they can cause disease. Fortunately, our bodies have an incredibly sophisticated defence system designed to protect us: the immune system.
Pathogens can be bacteria, viruses, parasites or fungi. Each one carries unique proteins on its surface, known as antigens. When a pathogen enters the body, the immune system recognises these antigens as foreign and begins producing antibodies to fight the infection and prevent illness.
Once the immune system has overcome the pathogen, it creates memory B cells. These cells “remember” the specific antigen, meaning that if you’re exposed to the same pathogen again, your immune system can respond quickly and effectively – often before you even feel unwell.
Vaccines work by safely introducing the immune system to a harmless version or component of a pathogen. This trains the body to recognise and fight the real infection in the future, without ever having to experience the disease itself.
There are several different types of vaccines:
- Inactivated: contain dead (inactive) forms of viruses or bacteria
- Live-attenuated: contain weakened (attenuated) versions that cannot cause disease
- Toxoid: contain a harmful substance (toxin) that is produced by the pathogen that causes disease
- Subunit: contain fragments of the germ such as proteins or sugars
- mRNA: contain genetic instructions (mRNA) that tell your cells to make a harmless piece of the pathogen
- Viral vector: contain a harmless virus that deliver important instructions to your cells so they can learn to recognise and fight a pathogen
Why We Vaccinate When We Do
The Joint Committee on Vaccination and Immunisation (JCVI), an independent group of experts, continuously reviews evidence to decide what vaccines children need and when they should receive them. The schedule reflects years of scientific research into how children’s immune systems mature and when different diseases pose the greatest threat.
During pregnancy, mothers pass on their antibodies to their babies through the placenta (the organ that provides blood and nutrients to the baby, and removes toxins).
Once the baby is born, these maternal antibodies offer some protection in the first few weeks of life (known as passive immunity).
The first round of childhood vaccines is scheduled for 8 weeks, as by this time the immunity offered from maternal antibodies has started to decline, and baby’s immune system has started working enough to be able to mount an immune response without becoming overwhelmed.
The rest of the vaccine schedule is set based on these factors:
- When diseases are most likely to cause illness.
- For example, whooping cough is most likely to cause death in those less than 3 months old, so the first dose of the vaccine is scheduled for 2 months (when passive immunity from maternal antibodies is waning, and the infant is still at high risk).
- When the vaccine is most likely to elicit the best immune response.
- For example, the Measles, Mumps and Rubella (MMR) vaccine is typically given at 12 months old, because the passive immunity from maternal antibodies can make it less effective.
- Whether more than one dose is needed for a effective long-term immunity.
- For example, 3 doses of the 6-in-1 vaccine are needed for full benefits.
Understanding The Role of Herd Immunity
Vaccination doesn’t just play an important role in protecting an individual child – it is crucial to protect whole communities too. When enough people are immune, infectious diseases struggle to spread at all, and in some cases can become completely eradicated (take smallpox, for example!).
This community-level protection is especially important for vulnerable children, such as newborns who are too young to be vaccinated (but at high risk of severe disease and death), children with immune disorders (“immunosuppressed” – where their immune system doesn’t work as well as it should), or those undergoing cancer treatment or with severe allergies that may restrict certain vaccine types.
For these vulnerable groups, herd immunity is life-saving. But this protective shield only works when vaccination rates stay high and schedules are followed consistently.
We’ve seen the effects of this recently. Look at the recent Measles outbreak – this is one of the most contagious illnesses humans have ever faced, meaning it spreads rapidly (1 person alone can infect up to 18 other people!).
For herd immunity for Measles to occur, 95% of the population needs to be vaccinated. This keeps the remaining 5% of the population safe, including the children who are unable to take the vaccine. As soon as the vaccination rate dips, outbreaks can occur, like we’ve seen across the UK and Europe in the past couple years.
What Do We Vaccinate Against and Why?
Vaccines protect against a range of serious diseases – some of which are now rare in the UK thanks to widespread immunisation. As a result, we might not be aware of the reasons we vaccinate against them in the first place!
Here’s a quick guide to what we vaccinate against and why it matters:
| Disease | What it is | Symptoms | Why it matters |
|---|---|---|---|
| Diphtheria | A bacterial infection most commonly caused by Corynebacterium diphtheriae. | Sore throat, swollen glands, a thick grey-white coating in the throat, and potentially breathing difficulties. | In the 1940s, around 4,000 people died each year in the UK from diphtheria. Vaccination has eliminated deaths from this disease in children today. |
| Tetanus | A bacterial infection caused by Clostridium tetani, which is found in soil and manure, and enters the body through open wounds. | Painful muscle spasms, “lockjaw,” fever, and in severe cases, death. | Since the tetanus vaccine, was introduced in 1961, cases in children are extremely rare. Between 1984 and 2022, almost all cases occurred in adults over 25, with none in children under five. |
| Haemophilus influenzae type B (Hib) | A type of bacterial infection. | Cause life-threatening infections like meningitis or epiglottitis, mainly in babies and young children. Symptoms depend on the infection. | The Hib vaccine has reduced severe disease in children by over 90%. |
| Hepatitis B | A viral infection of the liver spread through blood or bodily fluids.. | Yellowing of the skin/eyes, pain in the upper tummy, tiredness. | It can cause long-term liver damage, including cirrhosis and liver cancer. Vaccination protects children and young people before they are at higher risk of long-term liver damage (90% of infants with acute hepatitis B will develop chronic hepatitis). |
| Meningitis | Caused by several bacteria (e.g., meningitis B), viruses, and fungi. | Non-blanching rash (a rash that doesn’t fade when you press a glass to it), high fever, neck stiffness, photophobia (dislike of bright lights), and confusion. | Bacterial meningitis is fatal in 1 in 10 cases. Vaccines have significantly reduced cases in children. |
| Whooping cough (Pertussis) | A bacterial infection caused by Bordetella pertussis. | Severe coughing fits which may be followed by a “whoop” sound (gasping for breath between coughing fits). It is also known as the “100-day cough” as the cough can last around 10 weeks. | Vaccination protects both babies and pregnant women who pass antibodies to their unborn child. Before the vaccination, around 10% of children with whooping cough died from it; now, it is up to 84% effective at preventing the disease, and 91% effective at preventing hospitalisation. |
| Polio | A type of viral infection. | Symptoms include a high temperature, neck stiffness, fatigue, vomiting, headaches, and muscle pain, paralysis. | Thanks to vaccination, there have been no cases in the UK since 1984. Prior to the vaccine being introduced in the 1950s, up to 750 deaths would occur each year. |
| Rotavirus | A type of viral infection. | Severe diarrhoea and vomiting, and subsequent dehydration in infants. | Vaccination has drastically reduced hospitalisations, as it prevents infection in 8 out of 10 cases. |
| Measles, Mumps, Rubella (MMR) | Viral infections. | Symptoms vary depending on illness, but generally include cold-like symptoms and a rash, Cause serious complications, including deafness, pneumonia (infection of the lungs), meningitis and encephalitis (brain swelling). If a woman gets rubella when pregnant, it can lead to miscarriage or severe birth defects. | After the MMR vaccine, 99% of people are protected against measles and rubella, and 88% will be protected against mumps. Prior to the vaccine, 80% of the population developed measles in childhood. |
| Human Papillomavirus (HPV) | A type of viral infection. | Does not usually cause symptoms. Linked to cervical cancer, as well as other cancers e.g., penile cancer in men. | Vaccinating adolescents before exposure provides strong, long-lasting protection; a study published in the Lancet reports that the vaccine reduces cervical cancer rates by almost 90% in women in their 20s who were offered it at 12-13 years old. |
| Influenza (Flu) | A type of seasonal viral infection. | Fever, cough, sore-throat, headaches, tiredness. Infection can be severe in young children, older adults, and people with chronic conditions. | Annual vaccination helps reduce illness and hospitalisations, with this year’s vaccine set to reduce hospital attendances in children by 70-75%. |
What Are The Risks of Vaccinating Children?
No medical treatment is completely risk-free – and that includes vaccines. But it’s important to understand two things:
- The risks from vaccines are extremely small.
- The risks from the diseases they prevent are far, far greater.
Here’s what parents should know when weighing up those risks.
Common Side Effects
These are signs the immune system is responding – not that the vaccine is unsafe.
- Sore, red, or swollen area where the injection was given
- Mild fever
- Fussiness or irritability
- Tiredness
- Loss of appetite
- Mild rash (after some vaccines like MMR or chickenpox)
These usually appear within 24–48 hours and settle quickly without treatment. Regular paracetamol and ibuprofen will help with the fever, and encouraging fluid intake (giving small amounts regularly through a syringe) can help prevent dehydration.
Specific side effects can vary slightly depending on which vaccine is given. The CDC website gives a really thorough run-down on what you can expect from each individual one – click here to read more.
Uncommon Side Effects
Some children may experience:
- High fever
- Febrile seizures (fever-related fits)
- Temporary swollen glands
- Vomiting or diarrhoea (more common after rotavirus vaccine)
These can be upsetting but are typically short-lived, and in most cases, not dangerous. If your child develops any of the above though, it is always worth seeing a doctor.
Very Rare Side Effects
These are the ones parents tend to be most worried about.
Anaphylaxis (severe allergic reaction):
- Occurs in less than 1 in 1 million vaccine doses according to Resuscitation Council UK.
- Happens within minutes, which is why children are observed briefly after vaccination.
- Healthcare staff are trained and equipped to treat it immediately.
- Children who are allergic to a specific ingredient are given alternative vaccines where possible.
Some vaccines have extremely rare side effects associated with them, but these are monitored closely and the benefits still far outweigh the risks. For example, the MMR vaccine has a very small risk of temporary low platelet count* (known as Immune Thrombocytopenic Purpura), though this is typically mild and self-resolving.
*Low platelet count – platelets are involved in forming blood clots when we bleed, so a low platelet count increases the risk of bleeding.
Long-Term
Vaccines are one of the most closely monitored medical products in the world, and decades of data show they are safe.
To put things into perspective:
- Measles can cause pneumonia, encephalitis, and death.
- Meningitis can cause permanent disability e.g., deafness, within hours.
- Whooping cough can be fatal, especially in young babies.
- Polio can cause lifelong paralysis (you may have heard of people having to live in an “iron lung” in the mid-20th century).
So as with anything, even though there are risks with vaccines, the risks from these diseases are much higher. Vaccinating children remains one of the safest, most effective ways to protect their health.
In Summary
Vaccines have transformed child health. Diseases that once caused widespread disability, long-term complications, and thousands of deaths each year are now rare – not because they disappeared naturally, but because vaccination works.
Childhood vaccines are rigorously tested, continuously monitored, and given at specific ages to offer the strongest protection when children need it most. While mild side effects are common and very rare reactions can occur, the risks from these illnesses are significantly higher than the risks from the vaccines that prevent them.
As clinicians, we recommend vaccination not because it’s convenient, but because the evidence overwhelmingly shows it saves lives – especially in babies, vulnerable children, and those who rely on herd immunity for protection.
If you ever have questions or worries about a particular vaccine, speak to a healthcare professional who can discuss your child’s individual circumstances. No concern is too small, and no question is silly.
Protecting children is a team effort.
Vaccination is one of the safest and most powerful tools we have to do that.
Childhood Vaccination Schedule 2025
For reference, here is the latest childhood vaccination schedule for 2025, taken from that National Institute of Clinical Excellence (NICE).
| When to immunise? | What vaccine? | What diseases does it protect against? |
|---|---|---|
| 8 weeks old | DTaP/IPV/Hib/HepB (Infanrix hexa® or Vaxelis®) | Diphtheria, tetanus, pertussis, polio, Haemophilus influenzae type b (Hib), and hepatitis B virus (HepB) |
| 8 weeks old | MenB (Bexsero®) | Meningococcal group B (Men B) |
| 8 weeks old | Rotavirus (Rotarix®) | Rotavirus gastroenteritis |
| 12 weeks old | DTaP/IPV/Hib/HepB (Infanrix hexa® or Vaxelis®) | Diphtheria, tetanus, pertussis, polio, Hib, and HepB |
| 12 weeks old | MenB (Bexsero®) | MenB |
| 12 weeks old | Rotavirus (Rotarix®) | Rotavirus |
| 16 weeks old | DTaP/IPV/Hib/HepB (Infanrix hexa® or Vaxelis®) | Diphtheria, tetanus, pertussis, polio, Hib, and HepB |
| 16 weeks old | PCV (Prevenar 13®) | Pneumococcal (13 serotypes) |
| 1 year old | PCV (Prevenar 13®) | Pneumococcal (13 serotypes) |
| 1 year old | MMR (MMR VaxPRO® or Priorix®) | Measles, mumps, and rubella |
| 1 year old | MenB (Bexsero®) | MenB |
| 18 months old (if born on or after 1 July 2024) | DTaP/IPV/Hib/HepB (Infanrix hexa® or Vaxelis®) | Diphtheria, tetanus, pertussis, polio, Hib, and HepB |
| 18 months old (if born on or after 1 July 2024) | MMR (MMR VaxPRO® or Priorix®) — check first dose given | Measles, mumps, and rubella |
| 2 or 3 years old (on 31 August 2025) and all school aged children (from Reception to Year 11) | Live attenuated influenza vaccine LAIV (Fluenz®). Use inactivated flu vaccine if the child is in a clinical risk group and LAIV is unsuitable | Influenza (each year from September) |
| 3 years 4 months old | DTaP/IPV (REPEVAX®) | Diphtheria, tetanus, pertussis, and polio |
| 3 years 4 months old | MMR (MMR VaxPRO® or Priorix®) — check first dose given | Measles, mumps, and rubella |
| 12–13 years old | HPV (Gardasil® 9) | Covers HPV types 6, 11, 16, 18, 31, 33, 45, 52 and 58, giving protection against cervical cancer and genital warts |
| 14 years old (school year 9) | Td/IPV (REVAXIS®). Check MMR status | Tetanus, diphtheria, and polio |
| 14 years old (school year 9) | MenACWY (MenACWY — Nimenrix®, Menveo®, or MenQuadfi®) | Meningococcal groups A, C, W, and Y disease |
The Health and Healing Narrative 
Leave a comment