monoclonal antibodies

I have had the Evushield monoclonal antibodies, for (some amount of) protection against covid. The factsheet didn't answer my questions -- how soon will I be protected, and for how long -- and the nurse said to ask my doctor. I left a message with his office, and also mentioned those questions on a discord server.

A medical person who hangs out there said that the time to them being effective should be "quick, on the order of hours" and that the answer to the other question is more complicated. Half-life in the bloodstream is probably about for weeks, but to actually answer that question, even approximately,a person would need to know how many antibodies they injected and how many are needed to be significantly protective.

Evusheld (monoclonal antibodies)

Poking around a little, I found that (a) Evusheld is supposed to provide at least six months of protection, but (b) it may be less effective against omicron than against earlier variants, so (c) the FDA doubled the dosage last month, from 150 mg each of the two antibodies, to 300 mg each.

This is for pre-exposure prophylaxis, or PrEP, an acronym that some articles are assuming (correctly, in my case) that the reader knows.

The protection is at its strongest right now, and will diminish over time because the number of antibodies in the patient's system diminishes.

Putting this here largely for my own reference.

ETA 3/18: I found the AstraZeneca factsheet on Evusheld for medical providers, which includes the pharmacology: half-life is a mean 87.9 days (SD 13), which makes six months of protection seem plausible. (The person I talked to yesterday was guessing that the half-life would be about four weeks, based on the half-life of IgG treatments for hepatitis B.

[apparently it's "Evusheld," no i.}