As with all good internet journalism, the answer is at the end:
> The immune system is 'not a muscle.' All this begs the question: Will kids have more severe infections after the COVID-19 pandemic if their immune systems missed out "training" during winter lockdowns? Carsten Watzl, the secretary general of the German Society for Immunology, says we may see more infections, but not necessarily more severe ones.
TL;DR: Eating dirt won't work out your immune system because it doesn't work like that
Exposure to smallpox wiped out populations in two continents from no prior exposure. The quoted “not necessarily” isn’t a ringing endorsement. Chickenpox is another example of early exposure/vaccine or very bad things happen.
> Chickenpox is another example of early exposure/vaccine or very bad things happen.
Side note, even early exposure may not help. I got it twice and the second was rough. It also carries a higher risk of shingles later in life and could impact the nervous system. Please consider vaccinating your kids against chickenpox.
How come it’s not a muscle if the vaccination works?
Obviously getting more sick isn’t going to make your immune system stronger, but just getting sick is going to make it learn how to make antibodies for specific illnesses.
> The immune system is 'not a muscle.' All this begs the question: Will kids have more severe infections after the COVID-19 pandemic if their immune systems missed out "training" during winter lockdowns? Carsten Watzl, the secretary general of the German Society for Immunology, says we may see more infections, but not necessarily more severe ones.
TL;DR: Eating dirt won't work out your immune system because it doesn't work like that