> Vaccination makes you much less likely to get sick in the first place

Do you have a reference for this claim? Nearly everyone I know that has caught it and has gotten sick in the past 2 weeks has been vaccinated, sometimes boostered as well. I don't think this claim is true with Omicron.

Vaccination makes you less likely to end up on a ventilator.

I have seen much discussion of vaccines being less effective at preventing infection with omicron but no indication of them being 0% effective. Of course, it will probably be at least a few more weeks before we have good overall data on this (e.g. December/January case rates among vaccinated vs unvaccinated).

And in a big storm, even everyone being 25% less likely to get infected impacts rate of transmission, which is the big one for resource constraints and such.

> no indication of them being 0% effective

But there is no data to indicate that it's >0% effective either. So until we have data to back things up one way or the other, talking about it just creates more science disinformation.

That's quite the statement.

Early studies suggested that vaccine antibodies were much weaker but boosted individuals still had antibodies that had some effect on omicron, and gave no reason to believe that non-antibody parts of the immune system would have 0% effect. So based on that, and high level of protection against previous strains, my default assumption would be "some, but much lower, protection."

Then, as of Dec 26, being vaccinated in CA still resulted in a much lower case rate per 100K: https://covid19.ca.gov/state-dashboard/#postvax-status That likely isn't 100% omicron data, but the ratio looks the same as what it was before, so still not reason to drop my belief to 0%.

It is quite the leap to say "new strain, I should restart my assumption at 0% effectiveness."

Not saying restart all assumptions. I am saying that whatever you say should come with the "based on the previous..., it may or may not apply to current..." proviso.

Yep, county by county in the USA, as of Sept 2021, higher %age vax populations is correlated with lower case numbers.

Strangely, you can find this information in Fig 2 of this short anti-vax paper claiming the vaccine doesn't correlate with case numbers at all.

I don't blame people for being confused.

https://link.springer.com/content/pdf/10.1007/s10654-021-008...

The problem is that it doesn't show in the stats in practice. In the UK, the % of positive covid tests that are vaxed pretty much follows the % of people vaxed in the population (by age). If vaxed people were less infectious, you would expect the virus to circulate much more in the unvaccinated population. Particularly given that vaccine hesitancy isn't homogenously distributed in the population.

What exactly do you mean by "% of positive covid tests that are vaxed"?

In the US, with the delta wave, case-rate-per-100k-people very much showed that the vaccinated were less likely to catch Covid. For instance: "From December 20, 2021 to December 26, 2021, unvaccinated people were 3.9 times more likely to get COVID-19 than fully vaccinated people." (with a chart showing the trend similarly for months). https://covid19.ca.gov/state-dashboard/#postvax-status

I expect the omicron wave to be less dramatically tilted, but that there will still be some difference.

For instance 79% of the people >18yo who tested positive in December were vaccinated. And that's pretty much the % of people over 18 that are vaccinated in the UK. You get pretty much the same result for each age tranche:

                 Positive   of which     % pos test  % population
   Age            Tests      vaxed      vaccinated   vaccinated
   <18           395,335     57,284        14%        35%
   18-29         257,526    181,705        71%        60%
   30-39         254,435    193,623        76%        65%
   40-49         230,670    195,908        85%        77%
   50-59         147,033    129,440        88%        85%
   60-69          58,233     51,037        88%        90%
   70-79          18,858     16,263        86%        95%
   >80             9,067      7,658        84%        95%
   Total > 18    975,822    775,634        79%         

p36: https://assets.publishing.service.gov.uk/government/uploads/...

You had the same outcome in November, i.e. pre-Omicron.

Ah, yes. That's not a very useful stat compared to something like case-rate-per-100K since the denominator could be all over the map.

What's the case rate per 100K at the population level there?

Edit: actually, didn't find exactly that table, but did find a section in the doc you link, https://assets.publishing.service.gov.uk/government/uploads/..., on page 14, that shows vaccine effectiveness remains against symptomatic disease as a result of a study against delta and omicron both. But I would love to see the overall case rate to know about asymptomatic disease too.

Not sure what you mean by denominator? The denominator for vaxed positive cases is all positive cases. The denominator for vaxed in the population is total population (within the age range).

The % per 100k is available p40 of the same pdf. But I find that much harder to read given that the size of the vaxxed and unvaxxed populations vastly differ.

In "percent vaxxed among positive tests" you're only looking at those who got tested and were positive at a snapshot in time. At the very least, you also need to include all the people who tested negative. You complain that the size of the vaxxed and unvaxxed populations are vastly different but then use numbers where you look at just positive tests, ignoring counts or negative counts. That gives you numbers with even more potential sources for skew!

The table on page 40 is consistent with US data, where case rates at the population. It says to read in conjunction with pages 32 to 34, which basically says "stats won't be as accurate as formal assessment of vaccine effectiveness, please see the formal data." The formal data suggests effectiveness against transmission. The raw cases-per-100k numbers agree. Yet you latch onto a different number - another one that the report says isn't authoritative for those purposes either - to claim the data shows ineffectiveness! That seems backward.

The UK is considerably more vaxxed and boosted, enough that the dynamics could be different.