Didn’t we establish last week the vaccine is not effective at stopping the spread of the virus?

No.

The vaccines are not 100% effective at preventing spread (nor for preventing serious illness, for that matter).

That is not even remotely the same as "not effective".

In practice, the vaccines (with the possible partial exception of the J&J single dose) provide significant reduction in both spread and serious illness.

That vaccines reduce spread significantly is possible, and we can hope that they do, but it is not proven yet.

Depends on how you define effective.

Forever? No. Perfectly? No.

They do have an measurable impact on transmission, especially soon after vaccination. https://www.nature.com/articles/d41586-021-02689-y

No: https://www.nbcnews.com/health/health-news/vaccinated-people...

It's not a binary yes-no question. It is still effective at stopping the spread of the virus, though not perfect.

What exactly you would consider "effective"?

This[1] study suggests that there a brief period of significant reduction (~three months), followed by a period modest to no risk reduction, followed by a period of increased risk.

This[2] study found no correlation between vaccination rates and viral spread.

[1] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3949410

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8481107/

The first study is clearly underpowered to say anything about the risk after more than around 150 days. This can be seen in figures 2 and S1, where the confidence intervals get larger than the effect size at around this point. Combining multiple age groups together also leads to a large risk of getting incorrect results due to Simpson's paradox [1]. But with so little data, the authors probably couldn't stratify for age groups without the confidence intervals exploding.

A much larger study from the US [2] shows no measurable decline in the protection against hospitalization due to COVID over more than 5 months after vaccination.

[1] https://www.covid-datascience.com/post/israeli-data-how-can-...

[2] https://doi.org/10.1016/S0140-6736(21)02183-8

The way I see it, both studies show effectively the same result with similar confidence intervals. The US study however covers a shorter timeframe.

As far as hospitalizations go, I am not arguing with that, vaccines clearly reduce disease burden. The question was: Are vaccines effective at stopping spread? Many countries are experiencing record infection rates with a large majority of the population vaccinated. This suggests to me that vaccines are not effective in that regard.

It's not quite a binary yes-no question, but the vaccines not being effective enough for it to be possible to achieve herd immunity through vaccination alone makes a huge difference in how widely the virus ends up spreading.

More or less yes. The initial narrative of the jab as panacea has since evolved. The talking point now focuses on reducing hospitalization and death. The bit about the jab stopping transmission has been dropped as the number of so called breakthrough cases increases. Press Secretary Jen Psaki comes to mind.

Stopping entirely, no. Reducing, yes.

If everyone was vaccinated it would make a big difference.

People act astonished the COVID vaccines aren't perfect. You mentioning universal vaccination is such a key point. Let's look at smallpox.

We eliminated smallpox. Amazing! Yet, first, the smallpox vaccine wasn't perfect. It was 95% effective against infection. I would bet it's actually less than that. They probably mean symptomatic infection, because who was widely testing asymptomatic vaccinated people for smallpox? In contrast, symptomatic smallpox patients are pretty obviously and unambiguously infected with smallpox.

Second, what's particularly interesting is if you were the only smallpox-vaccinated person in a house of a couple others, the vaccine efficacy fell to about two thirds.

This isn't a world apart from the COVID vaccines. Two doses protects you 92-95% against severe disease. And two doses reduces the rate of transmission, if you end up infected, by 50% (this was 80%, pre Delta).

As I said, people act astonished the COVID vaccines aren't perfect. In reality, they're just focusing on COVID efficacy in ways they never have with other vaccines. The COVID vaccines are substantially more effective than your typical seasonal flu jag, or the BCG. COVID vaccines are not a world apart in efficacy than the Smallpox vaccine—and we beat smallpox! Smallpox elimination required universal vaccination, but we managed.