Immunisations: An Overview
The developing immune system in babies and children
The human body’s immune system is its defence system which protects it from infection, disease and various other environmental threats to its survival. Without it, we would become sick and die. The way our immune system grows in strength is by encountering new bugs and learning from that experience so that, the next time it meets the same type of bug, it recognises it and mounts a rapid, effective response thereby protecting the body from sickness or death. This ‘learn and respond’ system is vital to the development of the immune system, and to the survival of baby or child. This is where immunisations play a part (see below).
From 9 weeks of pregnancy the unborn baby (‘foetus’) starts to develop an immune system. However, the baby in the womb is ‘cocooned’ and sheltered from infection by its mother so it cannot learn from exposure to infection and therefore cannot grown in strength. Thus, what little ‘memory’ of infection (and hence defence system) a newborn baby has, is whatever has been conveyed to it by the baby’s mother (through the womb). This ‘passive’ immune system is all that the baby has to protect itself at birth. In fact, other parts of the body’s defences (e.g. proteins which are on the inside lining of the breathing tubes and gut) do not even start to be produced until 2-3 weeks of age.
How immunisations work
The first time a body encounters a new infection, it does try to mount a response to fight that infection but its response is slow and is sometimes a very weak one. However, after this initial infection attacks the body, the baby/child’s body produces special ‘memory proteins’ which remember that type of infection. So when the body meets that bug again, it remembers and recognises it and thereby mounts a rapid and much more effective response.
This principle of ‘learn and respond’ is how immunisations work:
- Step 1 – The body is tricked into thinking it is being attacked by a bug (but its not really being given the actual dangerous bug) – that is what the vaccine is.
- Step 2 – In response to the vaccine, the body creates special memory proteins to remember that type of bug.
- Step 3 – The next time the body faces the REAL bug, it remembers from its first experience with the vaccine and this time produces a fast, powerful defence and attacks the bug before it can seriously harm the body.
Babies and children are at greatest risk of harm from infection because their immune system is so underdeveloped. It is therefore precisely at this early stage in life that vaccines are needed, so their bodies learn to defend themselves more effectively before they are overwhelmed by serious infections or diseases.
Unfortunately, the fact that the immune system is so underdeveloped is itself a challenge for immunisations.
- For example, polio (a severe, disabling disease) is vaccinated against but the body requires ‘reminders’ to keep its special memory proteins up to a good level in the body, in order to be effective. Each reminder (booster dose of the vaccine) pushes the blood level of the memory proteins to a higher and higher level…until it reaches a level which can be sustained by the body without further prompting.
- In fact, if a vaccine is given at too early a stage of immune system development, the body is unable to create a meaningful immune response at all.
So vaccines have to be given at key time points in a baby’s or child’s life, if they are to be effective in helping that baby or child develop a strong immune system.
What makes MERAS Children's Healthcare special?
Every doctor will understand how the immune system works. However, what makes childhood immunisation more challenging is that bodies of babies and children are constantly changing, growing and developing.
The immunisation service that MERAS Children’s Healthcare runs is delivered by Primary Care Paediatricians and Consultant Paediatricians, who have a much deeper knowledge of how the constantly evolving immune system of babies and children work. They use this advanced knowledge and skill to:
- Better understand the pros and cons of vaccines at different stages of a baby or child’s life.
- Soundly guide and advise parents on the suitability and timing of vaccines for their children.
- More effectively plan and tailor immunisation programmes for babies and children, where necessary.
- More safely administer the vaccines and, if necessary, recognise and deal with any reactions*.
* These are rare and so the average doctor does not see very many reactions in their career. Paediatricians, however, have a focus solely on child health and often deal with the more complex/riskier cases in babies and children as they have greater experience of vaccine reactions. So you know your baby or child is in safer hands.
List of vaccines
Please see below a list of some vaccines that we at MERAS Children’s Healthcare can provide:
- Haemophilus Influenzae Type b (Hib)
- Herpes Zoster (Shingles)
- Human Papillomavirus (HPV)
- Japanese Encephalitis
- Pertussis (Whooping cough)
- Respiratory Syncystial Virus (RSV)
- Tick-borne encephalitis (TBE)
- Vericella Zoster (Chickenpox)
- Yellow Fever