A young baby’s nervous system is a delicate thing. At first, almost every sight, sound, and smell is a new one – every interaction with the non-uterine world presents a new challenge to that tiny little brain. For a brand-new human being, it’s a pretty sudden transition from a quiet, dark, tiny universe to a great big noisy bright one, and their miniature nervous system kicks into overdrive to process and handle it all. But why should it have to? In order to protect babies from the difficulty of nervous system challenges, why not put them somewhere safe for the first few years of their life: a nice, dark, quiet box, maybe?
Of course it’s ridiculous to suggest that an infant’s neurological development would be well served by keeping him away from any challenge. New faces, voices, sensations, and scents are how babies learn – having to deal with the daily trials and tribulations of being ejected from the amniotic swimming pool is what helps babies mature from the admittedly adorable but somewhat potato-esque stage of life into thinking, rational beings. (The “rational” part takes a little longer – about 25 years, if my own experience is any indication.) No reasonable person would want to keep a baby “safe” from learning and developing by keeping him in a dark padded room for a few years … and yet, when it comes to another highly complex system in that same baby’s body, a lot of people are willing and eager to do pretty much the same thing.
As with a baby’s brain, a newborn’s immune system is something of a tabula rasa. During pregnancy, it’s the parental immune system that does all the heavy lifting – most infections can’t even get across the placenta in the first place, which means until birth, fetuses are very much in a dark quiet box, immunity-wise. When they make their debut to the world outside, that immune system needs to explore and learn and process just as the brain does – at least if it’s ever going to be of much use. And spraying antibacterial agents all over anything and everything in baby’s path turns the excitingly germ-riddled world all around into another dark and dull place for an immune system that’s trying to figure out how to interact with the outside.
Take a look a certain baby registries lately and you’ll see an incredible list of antibacterial products: wipes. Shopping cart covers. Picnic blankets. Hand sanitizer. Baby clothing. This probably sounds great to any number of nervous new parents looking to do the best by their kids. But everything around you (and inside you – by sheer numbers, there are actually more bacterial cells in your body than there are your own cells) is covered in a fine layer of microbes, and for the most part, those guys aren’t going to hurt anyone. What they do provide is an opportunity for your baby’s immune system to investigate, and to figure out how to organize some sort of response. The kiddo’s immune system has to learn how to pick out which cells in the body aren’t actually supposed to be there, and then how to blow them up like an overfilled water balloon. If the immune system never gets a chance to practice on harmless dog-drool bacteria, how’s it supposed to have a decent chance of doing the right thing when something serious shows up?
And don’t forget that most of the bacteria hanging around on your skin or in your guts aren’t out to get you – they’re harmless types, or even friendly ones, who aren’t doing you any harm. Antibacterial everything doesn’t distinguish, though; while your immune system can learn to tell friend from foe, antibacterial molecules are like phasers permanently set on “kill”. (This is a science column, I’m allowed to make Star Trek references.) If all the good guys get wiped out, that leaves an open opportunity for the creepy-crawlies you really don’t want around to take hold the next time you miss a spot with sanitizer, or when baby crawls off the picnic blanket and shovels a fistful of dirt in her mouth. Antibiotic resistance is becoming a huge problem, with the volume of antibacterial soap going down bathroom and kitchen drains across the country, killing off any weaker bugs and leaving the big bad “superbugs” lots of extra space to grow and flourish in their place.
Of course, all of this is not to say that you should let your kid play with rusty nails or used syringes – no more than you’d “teach” a newborn by blasting them with John Phillips Sousa at full volume during a laser light show. A tiny immune system can only do so much, and “so much” does not include mounting an appropriate response to serious diseases. While baby plays with soft cloth blocks, let her play with friendly bugs, too. If it’s practical for you, having a pet in the house is a good way to get your kid the good kind of immune exposure; but so is just being outside in the wide world: chewing on a leaf, licking the grass, getting the occasional cold. (You’re definitely still allowed to freak out a little if you catch your kid chewing on something gross, though. I caught my daughter playing in dog poop a few days ago, and I think I might let her out of the bathtub by Christmas.)
And don’t forget: leave those antibacterial products on the shelf! Give your kid’s immune system one (trillion) to grow on.
IMPORTANT FOOTNOTE TO ALL OF THE ABOVE: If a child is immunocompromised in any way, then none of this applies at all. HIV, chemotherapy, SCID, and other serious health issues mean some parents have every reason to scour bugs of any kind out of their child’s vicinity. Keep in mind that while sharing information about antibacterial no-no’s with parents you know can be helpful, going up to people in the supermarket to scold them about their use of covers is the opposite of that.