On 18/09/2020 01:22, Zenaan Harkness wrote:
On Thu, Sep 17, 2020 at 12:45:36PM +0100, Peter Fairbrother wrote:
On 16/09/2020 21:59, jim bell wrote:
Also, search 'covid ivermectin'
Doesn't seem to work, or at least not very well. Promoted by many of the same people who promoted chloroquine, incidentally.
Why do you say that "[ivermectin] doesn't seem to work, or at least not very well" ??
It is far easier to investigate drugs in cell cultures than in whole humans, so researchers try many drugs in cell cultures to see if they work. That doesn't mean they will work in humans (or not work in humans, you can miss potential treatments too), but it is fairly easy to do and gives some hints about what may work. You can also try a lot more different drugs in cultures than you could try in humans. Ivermectin has been shown to inhibit COVID replication in cell culture. It is very effective at doing this. But only at levels which are too high for use in humans. So, the theory goes, give it a try in humans at the highest sustainable doses and see if it works. A bit of a hail-mary, but it costs very little and the drug is already medically and legally characterised as safe, so you don't have to do safety testing and the trials are even cheaper and easier and quicker. Unfortunately politics has gotten involved, and politicians have invested political capital in the effectiveness of ivermectin. This complicates matters. Scientists have methods to find out whether a drug is safe and effective but they take time (and cost lives). When politics (or finance, or reputation) become involved that process is disrupted, and answers become nebulous, at least temporarily. Clinical trials of ivermectin have begun. Afaik no real big trials have completed, but early reports are not encouraging - I don't mean they are discouraging, but if it worked spectacularly we would have heard the trials people going yeah yeah yeah by now. If you do search for 'covid ivermectin' in google, on the first page you won't find any positive reports from the trials people of its use in humans. [1] It might still work a little: though I doubt it personally, that is still possible. I hope it does. But it isn't a spectacular success, unlike dexamethasone and conjecturally [2] vitamin D, because if it was by now the trials people would be doing handstands and cartwheels - and they aren't. BTW this is almost the same story of chloroquine in COVID. Works well at too-high-for-humans doses in cell culture, is perhaps over-enthusiastically reported by the cell-culture guys, gets picked up by politicians, but, as expected, doesn't work well, or possibly at all, in humans. I say "as expected" because both were hail-mary's, we pretty much knew from the start they were unlikely to work in humans at tolerable doses. If you read the papers carefully you will see that, but perhaps you have to read them carefully and know how such papers are written. As to the cell-culture-guy / political-pickup issue, the cell culture guys were excited not only by a vague hope of a treatment but also because they were learning things about how the virus works. In a hit-it-and-see-if-it-breaks kind of way, but sometimes that can be illuminating. As to the politicians, I guess they either don't have real science advisors or they ignored them. Peter Fairbrother [1] There was a positive report by Prof Mehra etc, but it was widely disbelieved and has been withdrawn. As has his chloroquine paper. It looks like he, or the statistics company, just made stuff up - scientists can be mistaken and even lie too, though that is (supposed to be) the cardinal sin. There have been other positive reports, especially from Australia, Florida and Utah, but these have been mostly anecdotal. Hey if people can say COVID doesn't exist, other people can also say that x or y cures it. Doesn't make them right. If you look carefully you may find that quite a few the people who once said ivermectin cures 100% are now saying, well, maybe it helps. There are reasons why we do double-blind trials, even though they may cost lives. Anecdotal reports are unreliable. [2] We know that people who lack vitamin D are more likely to die from COVID, but we don't actually know that giving people who lack it vitamin D will make them have a higher survival rate. It seems likely, and I assume so, but correlation does not imply causation, and we just don't know for sure. It is just an assumption. OT: Have you noticed, the "we expect that politicians lie" meme has grown to the extent that politicians now use the expectation to get away with outrageous lies and similar behaviours? "Hey, I'm a politician, you expect me to lie".