If these were internal memos among domain experts, then understanding the nuances between "100% effective" and "immune" would be expected. But when the vaccine is being sold to the general population as "100% effective" I think we're just talking about wordplay.

Those articles made some pretty strong claims, and I'm not really sure what else a layperson is expected to take away from this besides "100% I won't get covid".

> Covid-19 vaccine is 100% effective

> Researchers observed 18 Covid-19 cases among the 1,129 participants who were given a placebo, and none among the 1,131 volunteers who got the vaccine.

> Pfizer COVID Vaccine Is 100% Effective in Adolescents

> A two-dose series was 100% effective against COVID-19, which was measured between 7 days and 4 months after the second dose.