[Someone1234]

Unfortunately the only real answer to that is: We don't have the data on either question yet.

Hemagglutinin has 18 subtypes, this style of vaccines are targeting them all, but we don't have data on how complete coverage will be (and or how common a mutation exists that could allow partial of complete circumvention).

We also don't have data on how long before the immune system needs to be retrained (aka re-vaccinated).

This isn't to foo-foo this vaccine; this legitimately could create a "universal" vaccine that could last years with only some minor reformulation every so often to catch new sub-types of HA.

TL;DR: This thing could be great. We'll need more data to know.

[runsWphotons]

Is there any reason to think the immunity would last? Like is there evidence in animals? Because the one mRNA vaccine we gave had in people did not provide much immunity past three months. That was in environment of virus mutating, but so will the flu.

[jefftk]

> the one mRNA vaccine we gave had in people did not provide much immunity past three months

That's much more about the virus than the vaccine type, no? The non-mRNA vaccines acted similarly.

[runsWphotons]

I think it is both. The mRNA vaccine immunity did not wane just because of changes in the virus. That was probably a factor but in this case I don't think it was even the biggest one. The immunity just wanes, even to the same strain. It is to do also with the immune system itself.

[maxerickson]

The antibodies produced by any vaccination series wane, it isn't a surprise that it happened with the COVID vaccines. The mRNA vaccines do induce memory T cells, which is exactly persistent immunity, so the immunity doesn't 'just' wane.

Repeated doses of the vaccine broaden and increase the antibody response, so of course it makes sense to encourage them when infections are raging, and an annual booster will induce an antibody response, providing increased protection for a period of time, so of course it makes sense to encourage them, especially for more vulnerable people.

This inability to look at things in a sort of probabilistic sense, where things can be good without being perfect, is incredibly damaging.

[kungito]

If that was so then things like alergies and autoimmune diseases wouldn't be for life

[nradov]

The non-mRNA COVID-19 vaccines that targeted the entire virus rather than just the spike protein generally produced somewhat more durable immunity even after many mutations. In principle it might be possible to make mRNA vaccines that work in a similar way, so I don't think it's a fundamental weakness in the technology.

[lenkite]

The non-mRNA vaccines did not give increased susceptibility to myocarditis AFAIK.

[revelio]

They did. The AZ vaccine was not mRNA based and was pulled from the market because it killed so many people.

The vaccines had two problems:

1. Spike protein is nasty. It causes clotting and organ damage. Doesn't matter how it gets in your body: virus, mrna, adenovirus, classical grow-it-in-eggs.

2. mRNA drugs specifically rely on special coatings which were as recently as 2017 unable to launch on the market due to toxicity that develops after multiple dosings. There's no evidence this problem was ever solved and Moderna pivoted from drugs to vaccines specifically because they couldn't solve it, the logic being that with vaccines you only have to take them once to get a lifetime of protection so the toxicity doesn't matter (doh).

https://www.statnews.com/2017/01/10/moderna-trouble-mrna/

mRNA is a tricky technology. Several major pharmaceutical companies have tried and abandoned the idea, struggling to get mRNA into cells without triggering nasty side effects

Three former employees and collaborators close to the process said Moderna was always toiling away on new delivery technologies in hopes of hitting on something safer than what it had. (Even Bancel has acknowledged, in an interview with Forbes, that the delivery method used in Moderna’s first vaccines “was not very good.”)

nanoparticles created a daunting challenge: Dose too little, and you don’t get enough enzyme to affect the disease; dose too much, and the drug is too toxic for patients.

Moderna could not make its therapy work, former employees and collaborators said. The safe dose was too weak, and repeat injections of a dose strong enough to be effective had troubling effects on the liver in animal studies.

The drugs it is pushing along now, by contrast, are more modest, relying on single administrations of mRNA.

[MAGZine]

one thing that's important to remember is that there are degrees of immunity.

ending up with a cough is very different ending up in a hospital, needing a ventilator.

people forget that flu vaccines are important: many people die from the flu every year. even if flu vaccines don't 'last' in the sense that they might not stop you from getting any sort of sick, they almost certainly are effective in preventing major illness.

[runsWphotons]

Sure, but there are still tons of questions and tradeoffs.