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Comment by adgjlsfhk1 | Hacker News Reader

mrna vaccines are a lot harder for viruses to mutate away from (and easier to adapt if they do) because they let you target a gene sequence directly.

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That doesn't really make sense. Target specifically, and it only takes a minor mutation to escape.

A less-specific vaccine would create immunity against multiple targets, and would logically require more simultaneous mutations to create an escape variant.

Unless your goal is to sell a new vaccine every year (chase your own escape variants, immunity-as-a-service), then MRNA isn't obviously a win.

Not an expert, but couldn’t the mRNA vaccine target only part of the virus genome that’s stable across mutations/variants? That would give you a broad vaccine resistant to mutations

Stable across mutations? On what timeframe.. Its been stable so far.

However, create a population with narrow immunity based on a single protein, and you create a selection pressure that incentivizes mutations in that protein. Once a successful mutation exists, it has a wide open field to spread unchecked. With broad immunity (multiple proteins) it is much less likely that a variant can realize the multiple simultaneous mutations that would be required to spread effectively.

> Target specifically, and it only takes a minor mutation to escape.

1) Not all sections of a virus mutate at the same rate. Some sections of a virus are highly conserved or the virus simply dies. In Covid-19, for example, the spike protein seems to be difficult to change significantly as it provides the primary entry for the virus into cells.

2) mRNA vaccines tell your immune system "target this specific sequence" and can avoid problematic sequences.

Normally, you have no idea what section of the virus your immune system locked onto. Even worse, if your immune system grabs onto something common (EBV pieces causing MS or alpha-gal from a tick bite, for example), it can hose you bad.

Covid-19 is actually a great example. The spike protein was highly conserved until it became advantageous for it mutate to evade the highly-specific immunity created by mRNA vaccines. Then we got Omicron.

For which the original vaccines are still reasonably effective at keeping you out of the hospital (systemic immunity response).

I am awaiting the trials on the ones that actually provoke immunity in the respiratory mucosa. It would be very nice to not get Covid at all.

The one example of mRNA vaccines that we have has resulted in the viruses by and large mutating away from them and they haven't been adapted quickly.

virus mutation rate is proportional to number of infected people, so pandemics will naturally mutate faster. also, the vaccines have been adapted quickly. the pfizer bivalent booster came out 18 months after the regular covid vaccine (9 months after omnicron started circulating) and had extra omnicron protection. that's really fast for drug development (and approximately all of that time was the clinical trial. it's not hard to imagine in a decade or two, that we'll be able to speed up the approval time further as the manufacturers and regulators have more experience with mrna vaccines).

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