Do we have comparable results for challenge trials with other vaccines? I thought the 90% numbers for the COVID vaccines sounded bad until I read that other vac

Do we have comparable results for challenge trials with other vaccines? I thought the 90% numbers for the COVID vaccines sounded bad until I read that other vaccines we routinely use are in the 80s. Additionally, AFAIK we don't actually know if the vaccines prevent COVID infections at all, we just know they prevent severe illness. If a challenge trial provided enough evidence of that, why wouldn't that be sufficient?