Very interested in this question as well.

[EDIT: QUESTION BASED ON INACCURATE UNDERSTANDING OF J&J]
Booster for Omicron question:

Is there any reason why getting a J&J booster now would be a bad idea? (E.g., would it prevent you from getting an Omicron updated mRNA booster?)

Why getting the J&J might be a good idea:

The Moderna and Pfizer vaccines inject you with mRNA that tricks your body into manufacturing a piece of the Covid19 virus called its "spike protein." Your body then learns to recognize this specific protein and attack it.

However, the omicron variant has ~30 mutations that make it "spike protein" different from the original virus. 

Alternatively, the J&J vaccine injects you with a bunch of non-infectious copies of the virus. In this case, your body can learn to recognize and attack many different parts of the virus.

The best thing would be an updated mRNA booster that codes for Omicron. In the meantime, it seems like it would be good for people who are immunocompromised or otherwise pretty worried to get J&J. 

I found this very helpful and motivating to read — it feels like this made clear and specific some things I had more hazily been thinking about. Thanks for writing it up.

I'm interested in this question as well.

I like this a lot, and have found similar-ish framings useful in my own life.

I think the robustness-fragility point is a very good one, and want to highlight it as I haven't seen it in discussions about hubs much.

Thanks for doing this research.