A retrospective study identified nine ILI adult cases of COVID-19 from two hospitals in central Wuhan (2). We estimate that there were a total of 5,558 [95% CI: 2,761-9,864] cases of COVID-19 in adults during that 21-day period across the 13 central districts of Wuhan, ranging from 75 cases [95% CI: 37-133] in suburban Hannan to 711 cases [95% CI: 353-1,262] in central Wuchang, as indicated by shading (Table S1).