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.