Table 3. The day with the highest probability of the virus being first detected ($p(\cdot )\left)\right(\mathrm{i}.\mathrm{e}.,t_{max}=\arg \underset{\mathrm{t}}{\max }p\left(t\right)$, i.e., the mode), cumulative (F(⋅)) and new (p(⋅)) detection probabilities by day t_max, and the 95% highest density (time) interval (HDI) for virus detection for Wuhan and the other four hypothetical epicentres, assuming the day with the first non-zoonotic infection is day 1 and wastewater from all the inbound aircrafts to the 20 major airports are tested.

Epicentre	t max	p(tmax) (%)	F(tmax) (%)	95% HDI for detection
Wuhan*	42	10.5	73.5	[1,45]
Madrid	35	9.1	67.6	[19,40]
Miami	32	9.0	63.1	[19,38]
Mombasa	41	9.0	69.7	[27,47]
Mumbai	38	9.0	65.3	[24,44]

* Time series of modelled infection sizes and detection probabilities for Wuhan were truncated by 22 January 2020 (day 45), since people were banned from leaving the city except for special reasons since the city was locked down on 23 January 2020. The cumulative detection probability by day 45 for Wuhan was 0.93.