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Usually the recommendation to not undergo unnecessary medical action is because the action itself can be not great for you. Killing parasites can be difficult because, unlike most bacteria and viruses, parasites are eukaryotic (same as us). This means drugs designed to target parasites may also be likely to target our cells to some degree.

Most of the time treatment is fine, but in some people the side effects can be quite severe. This is the root of the recommendation to not do so unless you know you have a reason to.

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Other countries recommend routine deworming. So it must be a fairly close call.

And honestly I am very pro-science but the “do no harm” bias in medicine makes me fundamentally question a lot of the recommendations. If it was just slightly better to deworm, do you think they’d recommend it? And then face accusations after any side effects (even if it was statistically the right call to do).

Those countries have very different risk factors. How many people in your community would you say do not have access to a plumbed toilet? clean water?

Not trolling, but in certain cities the amount of human waste in the streets suggests the answer could be far from zero. These unsanitary conditions seem to me to be an additional risk factor that probably wasn't taken into account when the risk factors for 'wealthy countries' were being calculated.

IDK whether this is significant to the original question (de-worm or not) because I'm not qualified to speculate, but I think it certainly suggests that at least for some cities, the evidence should be re-evaluated with realistic sanitation conditions in mind.

> And honestly I am very pro-science but the “do no harm” bias in medicine makes me fundamentally question a lot of the recommendations.

It's really not that - people have a fundamental desire to take action to mitigate tail risk even when that action poses more actual risk. You have to look at risk-reward tradeoff across the population. Treating the entire population for a disease very few of them have will almost certainly yield more (and potentially more harmful) realized side-effects than the actual primary effects being caused by the disease itself. Especially when patients aren't seeking treatment, so are most likely asymptomatic.

Ditto testing low-risk populations for all sorts of conditions they mostly don't have. Even a test that is 99% accurate in a high-incidence population is going to be utterly ineffective when applied to the general population. Bayes theorem tells us this. The side effects up to and including death of investigating or treating these false positives adds up to a real net-negative situation.

If it was even an eency weency bit better to treat in the US I would say they would overwhelmingly do so because they'd be sued into the ground otherwise.

tl;dr: especially when it comes to treatments, action is not always better than inaction. Generally, the US medical system tends towards action.

> Even a test that is 99% accurate in a high-incidence population is going to be utterly ineffective when applied to the general population.

I read that sentence a few times. 99% accurate seems quite high. WSJ recently opined about the 1-in-5 cancer misdiagnosis rate.

https://www.wsj.com/articles/are-you-sure-you-have-cancer-di...

"Are You Sure You Have Cancer?"

The WSJ article is behind a paywall so I can't double check this, but you can have a 99% accurate test with a 20% misdiagnosis rate. The difference is that 99% is per-person, and 20% is per-positive-result. A rare condition will have more false-positives relative to true-positives than the test accuracy would indicate.

It's a bit easier to understand if you think of the extreme case: if the disease is completely eliminated than all positives are false-positives.

The point is that a test that has a guarantee like "out of 100 people who test positive, only one will turn out to be negative" (99% specificity) can have an arbitrarily high false-positive rate when applied to the whole population: if a condition affects 1 in 10k individuals, then out of 10k individuals that take that test, 100 will be positive, but only 1 will be a true positive. The rarer the condition, the more specificity you need in your test to have a low false positive rate.

Firstly, not all worms are created equal. The most common worms in NA and Western Europe (like pinworm) just aren’t that serious.

Second, absent actual testing, the risk/reward of deworming is very much a function of the likelihood that you actually have one or more of these worms. That probability is too low in, say, the US to give routing deworming positive expected value. It’s telling that even routine testing isn’t worth the time/cost.

Thirdly, it’s not like… _exactly_ clear that all of these parasites are a problem in the first place. Many of them are frequently asymptomatic with negligible long term consequences. There are even those who believe that the near eradication of hookworm and its minor gut immunosuppressive effect in the developed world is the explanation for much higher rates of inflammatory bowel disease. I that one, but the general idea is that a lot of these worms just don’t actually cause much harm.

And lastly, deworming medications aren’t exactly a joke. They can have serious risks associated with them. Overall it just doesn’t make any sense to routinely deworm in the developed world.

it actually has nothing to do with individual patient health. The reason why 'we' don't recommend it is because we want to spend money and resources on others. Its about cost. providing the cheapest treatment for everyone so that you 'maximize coverage'.

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