TrumpLyftAlles | 4 points | Sep 17 2020 05:27:52

TLA speculating about the relative cost-effectiveness of ivermectin vs vaccines

This is a thought-piece that I started to post to twitter, but gave up because twitter posts are maddeningly short. Again, let me know if you think I should delete it as inappropriate for the sub. Or just too dumb to keep.

Critiques and suggestions welcome of course.

Proposition: If ivermectin provides 90% prophylaxis against covid-19, it's a better solution than vaccines.

• It would be much cheaper.  
• It would likely be more widely adopted.  

• On the order of a hundred million more Americans would be protected. A vaccine probably won't get us to herd immunity; ivermectin arguably would.

• However, a difficult problem with the approach is making sure people take the drug.

So far, ivermectin is 99% effective at protecting against covid-19. Let's say the real number is 90%.

I (very roughly) estimate that would cost the US $2 billion/year to give every resident weekly doses. For India, $1.4 billion (more people, cheaper price).

The federal government has contracted to pay Pfizer about $20/dose. Two doses a year will be required. For 330 million Americans, that vaccine would cost:

330 * $20 * 2 = $13.2 billion/year.

How many Americans would be protected by the vaccine, compared to ivermectin?

I think a consensus opinion is that a good covid-19 will protect 70% of the population (based on listening to This Week in Virology so no link). The CDC will accept as low as 50%.

That's compared to our theoretical 90% for ivermectin.

Right now there's a lot of resistance to any vaccine, out of general distrust of the government. A June poll found that only 50% intended to get a covid-19 vaccine. 9% of the US are anti-vaxxers, according to this 2020-02 WashPo article. For the sake of discourse, let's assume that for covid-19, that 9% increases to 20%; 80% take the vaccine.

How many will be protected by vaccines, if 80% take it?

If 70% effective: 330 * .7 * .8 = 185 million Americans   If 50% effective: 330 * .5 * .8 = 132 million  

For India's 1.35 billion people, the difference between 70% and 50% protection is 272 million people, assuming 100% acceptance of the vaccine. Efficacy matters!

Even after the 80% take the vaccine, Americans probably still won't be at herd immunity level, the fabled 70%, depending on how many have had the virus, which is unknown at this time, and how effective the vaccine is. 80% adoption of a 50% effective vaccine would require 30% of the US to be already infected with coronavirus to reach the 70% herd immunity level. The official number (which is low, but not an order of magnitude low, pretty sure) is about 3% have been infected in the US.

Let's say 90% of Americans take ivermectin, which doesn't have an equivalent to Facebook anti-vax groups (yet) and has an unassailable safety record (4+ billion doses taken by billion(s) of people, < 6-8 deaths).

We adopted 90% prophylaxis as our assumption for ivermectin, so it would protect 90% of the 90% who take the drug:

330 * .9 * .9 = 267 million Americans  

267 million protected vs 132 - 185 million for the vaccine.

That's 81% protected. Herd immunity! The 9% current anti-vaxxers and 11% new anti-covid-vaxxers are safe!

If 90% of Americans take 90% effective ivermectin, then at least (267 - 185 =) 82 million more Americans will be protected, than will be from a good vaccine.

267 million protected with ivermectin vs 132 - 185 million with the vaccine. Arguably, the remaining 63 million will be protected by herd immunity, with ivermectin.

Cost to tax-payers for treating Americans:

Ivermectin:

The $2 billion estimate was for 330 million people. That's $6.06 per dose. Call it $6. We assumed 90% adoption.

330 * .9 * $6 = $1.8 billion  

Vaccine:

At $20/dose, 2 doses annually: $40/year  

At 80% adoption:

330 * .8 * $40 = $10.6 billion.

$10.6 - $1.8 = $8.8 billion more to protect 82 million fewer Americans, almost 6 times as much for the vaccine compared to ivermectin. Or $8.8 to protect (267 - 132 =) 135 million fewer Americans, if the vaccine is only 50% effective.

Vaccines will cost on the order of 6 times as much as ivermectin, protect in the vicinity of 100 fewer Americans, and probably not get the US to herd immunity while ivermectin very likely would.

But people would have to take a pill every week.

That's a really valid objection to ivermectin in lieu of a vaccine. Schools can check vaccination records. How do we make sure people take their ivermectin?

Perhaps ivermectin consumption could be enforced by only allowing pharmacies to dispense it, even though it's free to everyone and no prescription is required. Then pharmacy records could be checked. That doesn't prevent people from tossing their ivermectin into the bin, though.

Spot blood tests to check for ivermectin? Welcome to 1984.

Simple solution: ivermectin toothpaste!

Require ivermectin in all toothpaste, like fluoride, or like vitamin D in milk. The anti-ivermectinists would have to make do with baking powder or something.

Is this an insurmountable objection to adopting IvermecCine(tm) instead of a vaccine? Maybe. We need a robust randomly-assigned doubly-blinded trial with a nice big N to find out of ivermectin toothpaste works. (joke)

It's moot until more trials come in and a lot more people start to believe in ivermectin.

TL;DR: Given many assumptions, vaccines would require something like 6 times as much money to protect 82 million to 135 million fewer Americans, probably failing to reach herd immunity -- compared to giving weekly doses of ivermectin to every American, which would likely lead to herd immunity and protect all Americans.

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