Table 1 Transmission model parameters.

\(\beta\)

Transmission parameter per susceptible–infectious pair

\(\delta\)

1 / Latency period (days\(^{-1}\))

\(q_A\), \(q_{I_M}\), \(q_{I_S}\)

Proportions of infections that are asymptomatic, mild symptomatic, and severe, \(q_A+q_{I_M}+q_{I_S}=1\)

\(\alpha _A\)

1 / Duration of infectiousness among asymptomatic cases (days\(^{-1}\))

\(k_A\)

Relative infectiousness of asymptomatic cases compared to symptomatic

\(\alpha _{I_M}\)

1 / Duration of infectiousness among mild symptomatic cases, time until isolation (days\(^{-1}\))

\(\gamma _{R_M}\)

1 / Duration of isolation among mild symptomatic cases, remaining time to recovery (days\(^{-1}\))

\(\alpha _{I_S}\)

1 / Duration of infectiousness among severe cases, time to hospitalization (days\(^{-1}\))

\(\gamma _{H}\)

1 / Length of hospital stay (time until recovery or death) (days\(^{-1}\))

\(\gamma _{{\bar{H}}}\)

1 / Remaining time until recovery or death among hospital overflow patients\(^{-1}\) (days\(^{-1}\))

\(m_H\)

Case fatality ratio among hospitalized cases (HFR)

\(m_{{\bar{H}}}\)

Case fatality ratio among hospital overflow patients

\(k_n\)

Proportion of all contacts that happen with individuals from adjacent counties (as opposed to within the county)

C

Hospitalization capacity, may be constant or vary over time representing capacity increase intervention

\(E_0\)

Number of exposed individuals statewide at the time of epidemic onset (initial condition, see Supplementary Material for details)