They’re not saying there’s no decrease in asymptomatic cases, they’re saying they didn’t check for that. AstraZeneca’s study in the UK did surveillance testing of their study participants and found a significant drop in asymptomatic cases as well. Reasonable to assume the same is true with the Pfizer and Moderna vaccines.
I find it inexcusable that moderna and pfizer decided to not test for asymptomatic at all, instead focusing on the subjective criterion of being symptomatic
