Model assumptions
| General |
| 1. No birth, death or immigration. |
| 2. We divide the population into 2 groups: one consisting of individuals who follow stay-at-home policies (marked by subscript q) and another consisting of individuals who do not opt for this intervention (marked by subscript nq). Owing to influences of self-protection consciousness and severity of the epidemic, people are assumed to move from one group to another with stay-at-home rate (denoted by q(t)) or going out rate (denoted by g(t)). |
| 3. Each subpopulation is further divided into susceptible (Si(t)), exposed (Ei(t)), asymptomatic (subclinical) infection (Ai(t)), infectious presymptomatic (will eventually show symptoms) (I1 i (t)) and infectious symptomatic (I2 i (t)). |
| 4. Both Ai(t) and I1 i (t) are infectious virus carriers. Individuals in Ai(t) will never show symptoms, while individuals in I1 i (t) develop into symptomatic classes (I2 i (t)) after a specified period. |
| 5. Mild symptomatic infections (I2 i (t)) are a source of infection until recovery. However, they may choose to isolate themselves either at home or other places. If the quarantine is respected well enough, these infections will be fully isolated (W(t)). |
| 6. The fully isolated (W(t)), and the hospitalized (H(t)) who are severely affected do not contribute to infection transmission. |
| Household structure |
| 7. All households contain n (n = 3) individuals, and family members are homogeneously mixing (i.e., contacting each other randomly). |
| 8. The infection rate of the asymptomatic and symptomatic infectious individuals to the susceptible is the same among the household. |
| 9. Every family except for those with symptomatic members has an equal opportunity to be released from quarantine after the stay-at-home policy is relaxed. |
| 10. Households with infected symptomatic individuals will continue to be quarantined after the stay-at-home policy is relaxed. |
| 11. For family members following stay-at-home policies, susceptible Sq(t) will be infected only by infectious individuals in the home Aq(t), Iq1(t) or Iq2(t). |
| 12. When no infections are in a household, the family will be safe and will no longer be involved in the transmission of COVID-19. |