I'd definitely consider 50% efficacy against the most prevalent variant (by far) after 10 weeks to be "waning". That might change if we ever get a booster tar

I'd definitely consider 50% efficacy against the most prevalent variant (by far) after 10 weeks to be "waning". That might change if we ever get a booster targeted toward Omicron specifically, but we don't have one, and by the time we do, I'm sure there will be other variants around.