  We propose a time-fractional compartmental model (SEI$_A$I$_S$HRD) comprising
of the susceptible, exposed, infected (asymptomatic and symptomatic),
hospitalized, recovered and dead population for the Covid-19 pandemic. We study
the properties and dynamics of the proposed model. The conditions under which
the disease-free and endemic equilibrium points are asymptotically stable are
discussed. Furthermore, we study the sensitivity of the parameters and use the
data from Tennessee state (as a case study) to discuss identifiability of the
parameters of the model. The non-negative parameters in the model are obtained
by solving inverse problems with empirical data from California, Florida,
Georgia, Maryland, Tennessee, Texas, Washington and Wisconsin. The basic
reproduction number is seen to be slightly above the critical value of one
suggesting that stricter measures such as the use of face-masks, social
distancing, contact tracing, and even longer stay-at-home orders need to be
enforced in order to mitigate the spread of the virus. As stay-at-home orders
are rescinded in some of these states, we see that the number of cases began to
increase almost immediately and may continue to rise until the end of the year
2020 unless stricter measures are taken.
