COVID-19–a viral infectious disease–has quickly emerged as a global
pandemic infecting millions of people with a significant number of
deaths across the globe. The symptoms of this disease vary widely.
Depending on the symptoms an infected person is broadly classified into
two categories namely, asymptomatic and symptomatic. Asymptomatic
individuals display mild or no symptoms but continue to transmit the
infection to otherwise healthy individuals. This particular aspect of
asymptomatic infection poses a major obstacle in managing and
controlling the transmission of the infectious disease. In this paper,
we attempt to mathematically model the spread of COVID-19 under various
intervention strategies. The impact of various factors, such as the
presence of asymptotic individuals, lockdown strategies, social
distancing practices, quarantine, and hospitalization, on the disease
transmission is extensively studied. We consider SEIR type
epidemiological models, incorporated with social contact matrix
representing contact structures among different age groups of the
population. Numerical simulation of the model shows the dependence of
the second wave on the lockdown and its exit policies during the first
wave.