CDC study from 33 sites, 25 states showed vaccine efficacy (against Sx COVID) in HCP was 82% with ONEdose (Pfizer, Moderna) and 94% for TWO doses (same as RCTs). The efficacy of only 1 dose (of a 2 dose COVID vax) is likely to be 70- 82%. https://t.co/uQhUmjSsRd