Thanks for the source, I've been so curious about this information but it's hard to find.
I should have said "relatively effective", since I'm also under the impression that the vaccines weren't super effective at reducing transmission of the original variant (compared to vaccines against other infections). But I also haven't seen much data, I vaguely remember hearing something from the WHO like "60% effective at reducing transmission of original variant, 40% effective against Delta", but I don't remember.
I should have said "relatively effective", since I'm also under the impression that the vaccines weren't super effective at reducing transmission of the original variant (compared to vaccines against other infections). But I also haven't seen much data, I vaguely remember hearing something from the WHO like "60% effective at reducing transmission of original variant, 40% effective against Delta", but I don't remember.