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Charlotte Flanagan,
Earth Cradle Health

February 2023


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Immune System
Development in Children.

Being a mum to two grubby, but wonderful children, it has been my experience that children get sick with acute illness such as the common cold, or gut bugs often; particularly in the first 5 years of life. This is because their immune systems are still developing. They NEED to get sick, as inconvenient as it may be. While our tendency as parents is to minimize their suffering and do everything in our power to make them well again, it’s questionable whether this is the appropriate course of action…

Children are born with what is known as “innate immunity”, it is the non-specific arm of the immune system that attacks all invading bacteria and viruses in the same way – it is fast acting, causing a large amount of inflammation, and non-specifically destroying cells (including our own). It is the first responder to an infection, although its effectiveness is quite limited.


Then enter the “adaptive” immune response. This response is slower to initiate, taking about 3 days to get into gear, but its method is much more precise. The adaptive immune response is activated if the innate response has been unable to remove the infecting agent.


The way these two arms of the immune system work together is quite fascinating; the innate immune response will destroy a pathogen cell and present its DNA to the adaptive immune system, which then has the ability to remember the DNA of this virus or bacteria and specifically target ONLY those cells to fight the infection; sparing our own and limiting needless damage. The adaptive immune system then stores the DNA information away so if you come into contact again with a pathogen with the same, or even similar DNA, the adaptive immune system is quicker to respond as it remembers the pathogen and has immune cells primed and ready to destroy it; meaning the illness is much less severe and shorter in duration.


Babies and children don’t yet have this adaptive immune response hence why they pick up EVERYTHING! There is only one way to develop the adaptive immune system though encountering the pathogen, so their little immune systems can do what they were built to do, develop immunity.


It can be challenging to watch our little ones go down with an illness and stand idly by as they sweat, and cry, and sometimes vomit, and cry some more, and not sleep and…

But it is our job, to support their bodies to develop and grow as best we can.

A large part of childhood illness that makes most parents edgy, is fever. A fever is a part of the adaptive immune response and is something we need to consider supporting, rather than hindering. The body has an endogenous antipyretic system; an inbuilt “anti-fever” mechanism that will prevent a fever exceeding 41C. Research is yet to conclude what effect external anti-fever agents (such as paracetamol) have on this endogenous antipyretic system. Paracetamol has also been found to increase incidence of post infective illness, likely through the stripping of glutathione, an important nutrient needed for immune function.

Natural treatments can help support children to feel better while their immune systems wrangle with new pathogens. Vitamin C from food sources, extra fluids, water, soup and herbal teas, luke warm washers on hot tired faces, and of course extra love and support, but ultimately the thing they need most, is to just rest and ride out the storm that is immune system development.


When if at all, do we need to intervene?

A big part of natural medicine philosophy is minimal intervention, just enough to let the body get back on track and bring itself into homeostasis. Knowing that the adaptive immune system isn’t activated until around 3 days helps us have a bit of a timeline to go by in relation to when we may need to step in and help a struggling immune system. It could be helpful to let children ride it out for around 4 days and if there are still no signs of improvement, then step in with nutrient supplementation, herbal medicine or homeopathics. Every child is different. No one knows a child, like their parent does. Trust your gut and always watch for red flags such as abnormal breathing, not eating properly (especially babies), low urine output, a non-blanching rash, unusual blue tinge to skin or excessively high temperatures in babies under 3 months.


During the past few years, new perspectives on how we view, and approach illness have developed. It may be helpful to question if the fear that has surrounded acute respiratory illness has somehow changed the way we feel about and therefore treat acute illness. Given the past two years it is an absolute game changer that it has become more socially accepted to stay home when sick! It’s exactly what a developing immune system needs, but also inconvenient… So naturally many try and resolve illness immediately, in order to get on with life, when a lot of the time what little bodies need is to take the time to recover – not the extra consumables.


  1. Informed Health, Innate and adaptive immune systems, 2020

  2. Bone & Santich, Healthy Children, 2008

  3., red flags for babies and children, 2022

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