Table 1.

Model Parameters and Data Sources. Parameters with an age indicator (a) have separate values for the 30+ age ranges.

Symbol	Description	Values	Sources
Hd, α, τ	Number of COVID-19 outpatients in age group α in district d over time period τ	Estimated
r	Ratio of ILI outpatients that are COVID-19 positive versus influenza positive (adults over 30)	Age 30+: 0.61 [95% CrI: 0.20–1.64]	Ref. [9]: Of the 26 tested ILI throat swab samples taken from adults over age 30 who sought ILI treatment at two central Wuhan hospitals between December 30, 2019 and January 12, 2020, 7 tested positive for influenza and 4 tested positive for COVID-19. None of the cases tested positive for both viruses.
Nd	Age-stratified population sizes in district d	2010 population scaled by the ratio of the 2019 to the 2010 total Wuhan population	Sixth National Census of the People's Republic of China in 2010 [20] and total population of Wuhan in 2019 (11.08 million) [21]
Ωτ	Number of outpatient visits (all causes) in Wuhan across all ages over time period τ	42,274 and 38,702 over two weeks, respectively	China CDC weekly reports of outpatient visits in Wuhan, December 30, 2019-January 12, 2020 [9]
${\Theta }_{\tau }^{\alpha }$	Number of ILI outpatients in age group α in Wuhan over time period τ	Age 30+: 61 and 47, for each of the two weeks, respectively	China CDC weekly reports of ILI outpatients in Wuhan, December 30, 2019-January 12, 2020 [9]
Φτ	Percent of influenza positive tests	25% and 28.6% for each of the two weeks, respectively	Ref. [9]: 25%, 28.6% adult (30+) influenza positive among 160 ILI throat swab samples, from December 30, 2019 to January 12, 2020.
Td	Epidemic doubling time	7.3 [95% CrI: 6.3–9.7] days 5.2 [95% CrI: 4.6–6.1] days	Refs. [2] and [24]