The Hygiene Hypothesis

In these days when we are considering our kids back in school, it’s worth balancing our ideas of clean versus dirty, and what clean actually means. Does it mean a sterile, germ-free environment?

And if we were to live in a germ-free environment, what would happen when we came across a relatively simple germ? We might have no immunity to it, and a relatively harmless virus or bacterium could take us out, or require an enormous fight in order for us to overcome it.

Germy Kids

So, that spoonful of dirt we are all supposed to get during childhood is for the purpose of educating and strengthening our immune systems. Parents know that when we send our kids to school they immediately seem to get sick and bring all of their germs home to the family, so we can all sniffle together.

Photo: Sara Pflugg with Burst

Although very annoying for all, it is a sign that the family’s immune system is being challenged with simple colds and other reasonably innocuous germs. Why do we suddenly all get sick? Usually, it’s because we have brought unfamiliar germs into our circle. We actually get used to the viral and bacterial content of our own environment. This is part of the reason so many people fall sick after going on vacation.

These periodic illnesses are what keep our immune systems tuned up, creating B and T cells to recognize and keep up with the new germs in the neighbourhood. There is a balance between never being sick and being sick too often. If every cold of a season seems to take us down, there are indications that the immune system may be weak. If the immune system becomes a couch potato with a lack of exercise (“never sick a day in his life”), it may not be able to attack an invader who tries to break in the door.

Cleaning and Disinfection

We must protect against known and nasty organisms that might exist in our food or water without trying to sterilize our whole environment. We need to balance ideas of disinfecting kitchen surfaces (from, for example, possible salmonella contamination) with the notion that clean is clean enough. Constant disinfecting of our living spaces may be detrimental to our health, especially to our children’s health.

A study in 1985 found that as infectious diseases came down steadily in the Western world, there was a corresponding rise in immune problems, whereas the opposite was true in developing countries – they had a high rate of infectious diseases and a very low rate of allergic, immune and auto-immune diseases, such as inflammatory bowel disease and diabetes.

Photo: Fernanda Publio with Burst
Twig yes, metal pole, no.

How does this work? Part of the idea is that our good bugs become limited when we try to kill off all of the bad bugs in our environment, so that our friendly bugs can no longer protect us. They are victims of friendly fire. This happens with antibiotic use, some of which is very necessary. It also happens with overly cleaned environments, not to mention the toxicity of the cleaning agents themselves.

In 1989, David Strachan, epidemiologist at the London School of Hygiene and Tropical Medicine, observed that hay fever was less common among children with older siblings. He concluded that children growing up in larger families will be more exposed to microbes in early childhood, from contact with older siblings. Prenatal exposure of the mother to their unhygienic little darlings will also increase exposure of healthy dirt to the fetus. Strachan proposed that this exposure protects children from developing immune and allergic problems later in life.

All of those snotty noses turn out to be quite protective.

What About COVID?

Kids get COVID less and seem to transmit it less, according to MacMaster Dr. Jeffery Pernica, Head of the Division of Pediatric Infectious Disease. Getting them to understand the importance of hand washing, and of not coming to school when they’re sick is part of their overall training. Getting kids to wash their hands with repetition and fun will help much more than shaming, fear tactics or punishment.

If they do come down with it, the recovery rate, according to WebMD is 97% – 99.75%. Right now we are hyper aware of protecting our aged population and those whose immune systems are in some way compromised. Of this massive recovery percentile, an equal rate of recoveries happen at home, without medication, except for mommy care. And couldn’t we all use just a little more of that…

Wisely, Dr. Pernica also suggests the ability of parents to leave work at a moment’s notice in order to look after sick children. Too often parents, mothers especially, have to defend themselves at their work places when children are sick. They face the sighs, head shakes or outright aggressive comments about their commitment to the company, or snide remarks about excuses to go home.

It is difficult in these days to balance our need to protect against seasonal flu and COVID-19, while trying not to eliminate our stock of good bugs – our own internal flora, good gut bacteria or the friendly bugs that live on our skin. These are all protective and, in some cases, symbiotic. They live with us and there is mutual benefit to having them as friendly tenants.

Our gut flora is, in some quarters, considered its own organ, not just a collection of bacteria. These bugs are so important to us in their numbers and activities that without them we would cease to exist. It is widely said that we are mostly water. In truth, we are mostly bugs (bacteria, viruses and beneficial parasites). While there may be an “ick” factor with this, we have to make friends with the idea and protect them so that they can protect us.

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