Wednesday, April 7, 2021

Vaccine passports

This is Joseph.

Mark and I were discussing this tweet and how many assumptions it makes.

First, it looks at a case which is true for basically no actual vaccine, treatment, or protocol. What is 100% safe in life? Financial assets, even those backed by governments, can become worthless.  Just consider 1913 Russian government bonds or shares in Enron. Cars are not 100% safe, which is why we make other cars follow rules. Similarly, what medical treatment is 100% effective? Even very minor medical treatments can have complications. Statins save lives, but rhabdomyolysis does occasionally injure a user of statins. 

I am being pedantic because the assumption of no crossover requires perfect efficacy and safety (so that it can be treated as not having any positive herd effects). Furthermore, it presumes that all parties have access to a vaccine, all parties (even infants) can take the vaccine, and that there is no benefit in dropping the prevalence of the disease to reduce variants emerging. 

So, to be clear: the vaccines are not 100% effective and nobody has claimed otherwise. Pfizer, for example, is 95% effective against mild and moderate disease. Very happy to concede this point. Safety is a bit trickier, as we are still learning about the vaccines, but nobody disputes allergic reactions happen

It is a general principle of public health that requiring vaccinations is a great way to reduce disease spread. For example, it isn't a passport but you need proof of vaccination against measles to attend school. Or to take University classes as a student in health sciences. International travel used to require smallpox vaccinations and even today vaccinations are required for some countries. In other words, cases were a person could be a serious concern as a disease spreader have always been an issue, usually via quarantine in time periods prior to vaccinations

In other words, this stuff is just nuts. Wait until people find out about seatbelts. Until universal vaccinations are a reality then passports are just a good way to reduce disease spread, improve public safety, and rebuild confidence in public gatherings. 

1 comment:

  1. Joseph:

    I looked up this guy on twitter and . . . jeez, he's a step away from 4chan-type stuff. He's linking to Alex Jones fans. It's a scary world out there.

    But, yeah, the statistical error he makes is interesting. It's reasoning that could make sense in a deterministic world but completely falls apart under uncertainty. This suggests an interesting general question: what aspects of deterministic reasoning are robust to the addition of a small amount of noise, and what aspects fail?

    But, reflecting on this a moment, his reasoning is wrong even in a deterministic world! He writes, "If a vaccine were 100% safe and 100% effective, then somebody's decision to *not* take it would have no effect whatsoever on anybody else." But that's wrong! If a vaccine were 100% safe and 100% effective, then somebody's decision to *not* take it would definitely have an effect. By not taking the vaccine, you can spread the disease to other people who don't have the vaccine. This could kill people!

    If you want to argue against vaccines using cost-benefit reasoning, go for it. I doubt I'd be convinced, but you can lay out the costs and benefits and make your case. Maybe this guy feels the social costs are too high. But the direct benefits are clear---even more so if the vaccine is 100% safe and 100% effective. So I don't think this guy has thought this through at all.

    Looping back to the beginning of my comment: Maybe the problem is that he's tweeting into an echo chamber. Or, not quite an echo chamber---I see that many twitter commenters disagreed with him---but some sort of chamber where people immediately discount disagreeing arguments and just stick with their original position no matter what.

    I'm tempted to say that it's not even possible to try to reason with Alex Jones fans, but as a political scientist I know that people have complex mixtures of beliefs, so it's missing the point to just write off this guy as extremist fringe.