Why Do Kids Get Sick So Much?

This is the million dollar question for every new mom because kids get sick all the time. I mean ALL the time.  Here’s the thing – they’re designed to get sick all the time and the best news of all is that getting sick is actually the healthiest thing a growing immune system can do. Getting sick is how your kiddos immune system learns about the threats that are in the world as well as learns how to strengthen their own defenses. The human immune system is truly remarkable and the more opportunity it has to learn (which is getting sick), especially in the early years – the healthier it will be in the later years.

Kids Get Sick Because Kids Are Designed to Get Everything

Did you ever wonder why kids put EVERYTHING into their mouths?  Part of it is a deliberate system that is designed to get as much bacteria into them as possible.  Literally they are designed to pick up more bacteria to help them strengthen the flora in their gut, which is the protective bacteria, and also to help them gain exposure to pathogens so that their immune system can learn from them. Instinctive behaviors, like this one, always have an evolutionary advantage or they would have faded away with the generations. Clearly that isn’t happening because your kiddos put just as much stuff in their mouths as your great-grandparents kiddos did.  A great article by the NY Times said:

Since all instinctive behaviors have an evolutionary advantage or they would not have been retained for millions of years, chances are that this one too has helped us survive as a species. And, indeed, accumulating evidence strongly suggests that eating dirt is good for you.

“What a child is doing when he puts things in his mouth is allowing his immune response to explore his environment,” Mary Ruebush, a microbiology and immunology instructor, wrote in her new book, “Why Dirt Is Good” (Kaplan). “Not only does this allow for ‘practice’ of immune responses, which will be necessary for protection, but it also plays a critical role in teaching the immature immune response what is best ignored.”

Kids get sick - that's not usually a bad thing. Thanks to Badobadop at wikimedia commons for the image.

Kids get sick – that’s not usually a bad thing. Thanks to Badobadop at wikimedia commons for the image.

So How Much Sickness is Normal?

The average for kiddos who are in school or daycare is six to eight upper respiratory tract infections and two or three gastrointestinal upsets. As a parent, that is likely to feel like your kid is sick near-constantly and clearly that must be abnormal.  The reality is that they are doing exactly what they’re designed to do.

How Does This Help Their Immune System?

You have two different types of immunity. One is called innate immunity – this is the type that you’re born with. It doesn’t really need to learn from the outside world, it gives you protection from day one. This comes largely from your genetics and has the blanket program of attacking pretty much anything foreign but it isn’t good at mounting a quick response against particular invaders – that is up to the other system.  The other type of immunity is acquired immunity. This is what your kiddo (and you) are strengthening every time you get sick.  These are your specific defenses and this is the reason why vaccines or previous illness usually protect you from getting sick with that same thing again.  So, acquired immunity means if you get the chicken pox as a child, you won’t also get it as an adult unless something goes wrong somewhere because you have acquired immunity to it.  So essentially every time your kiddo gets a virus or bacteria they are protecting themselves from that virus or bacteria in the future and strengthening their defenses.



A University of Arizona study published in 2002 showed that children between 6-11 years old who had previously been in daycare or preschool were less likely to get sick than those who were cared for exclusively at home.  Of course, the trade off was that they probably got sick more while they were in daycare. Also there is strong evidence that having some natural childhood illnesses like measles and mumps protects from diseases later in life, including cancer.

Well-managed natural infectious diseases are beneficial for children.

When infectious diseases of childhood are not mismanaged by the administration of antibiotics, or by suppressing fever, the diseases prime and mature the immune system and also represent developmental milestones.

Having measles not only results in life-long specific immunity to measles, but also in life-long non-specific immunity to degenerative diseases of bone and cartilage, sebaceous skin diseases, immunoreactive diseases and certain tumours as demonstrated by Ronne (1985). Having mumps protects against ovarian cancer (West 1969).

The bottom line is that kids get sick because they’re supposed to get sick. They really are supposed to put everything in their mouths. They’re supposed to have exposure to all kinds of germs and bacteria and viruses.  Kids who get sick more as toddlers are less likely to get sick down the road and we’re just learning that the protection extends to diseases unrelated to the initial exposure. So if your kiddo is home sick again? Good for them.



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