Comment by cltby | Hacker News Reader

Comment by cltby | Hacker News Reader

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It's simply pathological to claim that we have NO DATA just because a large scale RCT wasn't performed.

For starters, we have profound differences in the attack curves between treatment and control group, starting about 14 days after administration of the first dose [1]. I don't have the numbers in front of me, but I'm going to guess the trial size is more than adequately powered to detect differences 27 days out.

All this is exactly as theory would predict. Seroconversion typically takes about two weeks. Once seroconversion happens, immunity lasts years (if not decades), which is why most booster doses are given years apart [2]. And any talk of "full efficacy" is confusing population statistics with individual outcomes. To say that Moderna is ~85% effective after one dose, as it appears to be, is to say that 85% of the population will produce antibodies after a single dose. There is no "partial immunity"--you're immune or you're not.

[1] https://www.ft.com/content/7cebed90-3267-4651-a249-56f5a9ae7...

[2] https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolesc...

There is no "partial immunity"--you're immune or you're not.

Is that true? (I'm not an immunologist; I genuinely have no idea.)

I'd have thought that it was all a statistics game: how many antibodies you have and how fast your white cells can respond to the threat before the virus got a foothold. In that model there is partial immunity: some people would win that race, and some wouldn't.

If I'm wrong about that I'd appreciate a better model. Thanks.

The OP's categorical statement on partial immunity is entirely false. Look at the Astrazeneca data in the Lancet. No hospitalizations in the treatment arm. That is evidence of "partial immunity."

Thank you.

What do hospitalizations have to do with immunity?

Presumably, that some people did get sick but not sick enough to be hospitalized. The vaccine was rated at ~90% effective, not 100%, so some people did get sick. But if they got lighter symptoms, that would qualify as "partial immunity".

90% efficacy does not mean that 100% of the population is 90% able to fight off the disease. It means that 90% of the vaccine recipients are ~100% immune, while 10% are ~0% immune. This has a biological basis: did they seroconvert or not.

It simply isn't workable to reason from lighter symptoms to "partial immunity." Let's pretend the vaccine didn't exist. Take someone with a mild case of covid. Would you say this person is partially immune? Or consider someone with no symptoms at all--are they completely immune? Since the vast majority of cases are mild or asymptomatic, are you prepared to argue that "immunity" is actually very widespread?

Again, your "some people win the race, some lose" analogy is on the mark. It's pointless to talk about "partial victory"

> some people would win that race, and some wouldn't.

You've basically answered your own question. At the population level, immunity is probabilistic. At the individual level, it's ~deterministic. Those who are challenged but stay healthy are immune. Those who are challenged but get sick are not immune. If we were to repeat the experiment, the individuals who stay healthy/get sick would largely remain the same. In this ex-post view of things, there's no "in-between." You got sick or you didn't, you're immune or you're not.

From an ex-ante perspective, we would instead try to predict whether a person will get sick or not. The answer to this largely depends on whether the body can generate a response to previously recognized antigens. This again is binary. You have memory B-cells due to primary response or you don't; you're immune or you're not.

Note that this isn't a "booster shot" in the sense of the boosters you are linking.

These are rDNA Prime/Boost vaccines, which is completely different to the conventional vaccines with the multi-year booster regime.

I agree that the 14 and 27 day attack curves should provide some efficiency data though.

Your cells will take up the mRNA and manufacture spike protein, which is the antigen of interest. We should expect this to be pretty similar to just injecting the antigen directly, as the other vaccines do.

We have data, but no information. We have to synthesize the data into information using analytical techniques or it is meaningless.

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