Fig. 4.

The plot of the sensitivity indices of $R_0$ depends on (A) The disease transmission rate of non-vaccinated susceptible population ${\beta }_1$, (B) The disease transmission rate of dose-1 vaccinated susceptible population ${\beta }_2$, (C) The disease transmission rate of dose-2 vaccinated susceptible population ${\beta }_3$, (D) ${\delta }_1$, the proportion of infected but asymptomatic individuals exposing symptoms, (E) The recovery rate of asymptomatic infected individuals from the disease ${\delta }_2$, (F) The rate of exposed individuals who are asymptomatic to the disease $\gamma$, (G) $\xi$, each population’s natural death rate, (H) The dose-1 vaccination rate ${\alpha }_1$ administered to non-vaccinated susceptible population, (I) The dose-2 vaccination rate ${\alpha }_2$ administered to dose-1 vaccinated susceptible population, (J) The booster dose vaccination rate ${\alpha }_3$ administered to dose-2 vaccinated susceptible population.