> and there are reasons why they're not part of any drugs

Caplacizumab (Cablivi®) is a Nanobody (2 VH units linked together) approved by the EMA since 2018 (and by the FDA since 2019).

Mind you this is used for TTP and thrombosis, where short lifetime is a benefit. You want to remove the clotting factor now, not forever. (We have drugs for that too.)

Short lifetime can be a benefit for anti-Covid medication too. An antibody could cross react with a vaccine and hamper the immune system response, preventing it from launching a proper reaction and creating proper immunity. You don't want the person having to wait for weeks while being vulnerable until they can get a vaccine after a successful therapy with antibodies.

But of course, distribution is a headache.

A person having an an immune system that can be vaccinated with traditional vaccines (including mRNA), while not developing meaningful resistance (such that a second infection isn't serious even if possible) from an infection where they needed antibodies, doesn't seem very likely. And if they were treated with antibodies once, they could probably just use them again, so it doesn't seem important.

Nevertheless, it would still be moderately impractical in the sense that a vaccination immunity should (probably?¹) be more effective than immunity after an infection, but it may not properly develop until the vaccine is administered without (much) antibodies present.

¹ is there any evidence or a sound supported theory that a coronavirus vaccine is more effective and/or long lasting than immunity after an infection?

Touche, there do seem to be approvals. I'll edit my post.

One example of a very new drug; do you have any others? Any studies on its efficacy and side effects?

It’s a bit unfair to ask the parent to do this legwork. The fact that it got approved implies that it is effective and that side effects are rare and/or relatively minor.

Edit:

From the phase II trial:

“ Adverse events overall were similar between groups, with the exception of bleeding, which occurred more often with the immunoglobulin treatment (54% versus 38%). The two participants who died were both in the placebo group.” https://www.medpagetoday.com/Cardiology/VenousThrombosis/561...

It does say in the article it could be a helpful treatment for people who have tested positive for covid. Do you think that's just hype, or could it actually be helpful?

Seems boilerplate "could be helpful to cure xxx" statements written in press releases and grants for most research findings; neutralizing antibodies do seem to help in mitigating worse outcomes (among others Lily sells a concoction) but even when they have good half lives it looks like the neutralizers don't do too much; there's no benefit I can see for something with orders of magnitude lower half life still.

“Could be” in this context is more like “hasn’t been conclusively proven impossible”. Unless somebody is taking about human trials it is exploratory and not worth getting anybody’s hopes up unless your hopes involve grant money and publishing papers.

Mostly hype.

Absolutely right, Pfizer has failed on those as drug candidates for the last 20 years.

I came here to same more or less the same thing. They are, however (potentially) a good analytical tool.

Also probably a good imaging agent, but then that's like the consolation prize for every "promising" targeting approach who's "only" flaw is a shitty half life, so no end to competition!

This is cheaper to produce and can be take more regularly than monoclonal antibodies. The more options the better!

The only places where short half life proteins have been useful is if you're delivering toxic substances and you don't want any off target effects (see BiTes - https://en.m.wikipedia.org/wiki/Bi-specific_T-cell_engager ) the technology behind the targeted becomes less relevant if you don't care about the half life. You can make antibody fragments that are only slightly larger that are still fine.

isn't the point to reduce severity... in icu with ventilator vs little cough? if viral load annihilated the immune response would be light and less damage to organs.