[anovikov]

Detailed results of clinical studies that were used to apply for emergency authorisation of vaccines were widely discussed in all kinds of press of all political leanings. They explicitly stated that there were no studies about probability of asymptomatic infection. IIRC Pfizer study counted as "positive cases" (for both vaccine and control group) the one that had both a positive covid test AND two of the six primary symptoms, or a positive test AND breathing difficulties/reduced blood oxygen levels, as a single sufficient serious symptom. They did not count asymptomatic infections.