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Comment by ars | Hacker News Reader

This is the wrong discussion - what's needed is a vaccine that actually lasts for more than 6 months before immunity fades.

I remember reading very early in COVID how experts said finding a vaccine would be very difficult because we've never been able to generate long lasting immunity to corona viruses. And they were hoping COVID would be different.

Turns out - it's not different.

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We are preventing development of serious disease with the vaccine. At the end of the day, that’s what should count.

> At the end of the day, that’s what should count.

no, that's just the most that could be achieved. The ideal, which is long lasting immunity, is not quite achievable atm (it seems).

I'd definitely accept reduction in severity, but would hope for a life long immunity.

The conversation around this could benefit from more precise language.

Long lived immunity against severe disease, driven by the T cell response against epitopes that are generally well preserved (>80% for spike protein, ~98% for non spike protein) [1]

≠

Immunity against infection, conferred by circulating neutralizing antibody, which last for a couple of months

Most vaccines blunt or prevent disease but not infection.

[1]: https://www.nature.com/articles/s41423-022-00838-5

> This is the wrong discussion - what's needed is a vaccine that actually lasts for more than 6 months before immunity fades.

I think your idea is what OP is discussing with “universal COVID vaccines” — generating broad immunity that new variants can’t escape so quickly.

The loss of immunity is not due to variants. The immune system itself simply starts forgetting.

What part of the immune system are you referring to? My understanding is that the initial set of antibodies wane over time but will be produced again if memory B cells encounter the same antigen. Similarly, T cells specific for an antigen will amplify in number if re-exposed to that antigen.

The serial interval of the virus is so fast that there's no way the T-cells and B-cells can keep up. Some sort of nasal vaccine could reduce infection for a few months but as far as I can tell it's impossible to make a long lasting (years) coronavirus vaccine that can prevent infection. Serial interval is too fast, antibodies wane too fast, your immune system is too slow. I could see a gene therapy/retrovirus thing that hijacks some cells permanently to produce antigens (or make it smarter and somewhat regulating like an HIV infection, if HIV is forever this could be too) so it's like getting vaccinated every minute of every hour of every day, forever. Alternatively, you could produce genetically engineered B-cells in the lab and inject them into people ('s bone marrow?) to constantly produce a very high dose cocktail of broadly neutralizing antibodies. Completely infeasible, too expensive, won't scale. Might work. None of these ideas would be approved for the general public in at least 25 years.

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