COVID-19: Risks of Re-emergence, Re-infection, and Control Measures -- A Long Term Modeling Study
Subhas Ghosh, Sachchit Ghosh
Received date: 29th September 2020
In this work we define a modified SEIR model that accounts for the spread of infection during the latent period, infections from asymptomatic or pauci-symptomatic infected individuals, potential loss of acquired immunity, people’s increasing awareness of social distancing and the use of vaccination as well as non-pharmaceutical interventions like social confinement. We estimate model parameters in three different scenarios - in Italy, where there is a growing number of cases and re-emergence of the epidemic, in India, where there are significant number of cases post confinement period and in Victoria, Australia where a re-emergence has been controlled with severe social confinement program. Our result shows the benefit of long term confinement of 50\% or above population and extensive testing. With respect to loss of acquired immunity, our model suggests higher impact for Italy. We also show that a reasonably effective vaccine with mass vaccination program can be successful in significantly controlling the size of infected population. We show that for India, a reduction in contact rate by 50\% compared to a reduction of 10\% in the current stage can reduce death from 0.0268\% to 0.0141\% of population. Similarly, for Italy we show that reducing contact rate by half can reduce a potential peak infection of 15\% population to less than 1.5\% of population, and potential deaths from 0.48\% to 0.04\%. With respect to vaccination, we show that even a 75\% efficient vaccine administered to 50\% population can reduce the peak number of infected population by nearly 50\% in Italy. Similarly, for India, a 0.056\% of population would die without vaccination, while 93.75\% efficient vaccine given to 30\% population would bring this down to 0.036\% of population, and 93.75\% efficient vaccine given to 70\% population would bring this down to 0.034\%.
This is an abstract of a preprint hosted on a preprint server, which is currently undergoing peer review at Scientific Reports. The findings have yet to be thoroughly evaluated, nor has a decision on ultimate publication been made. Therefore, the results reported should not be considered conclusive, and these findings should not be used to inform clinical practice, or public health policy, or be promoted as verified information.