The impact of the undetected COVID-19 cases on its transmission dynamics

OBJECTIVE: The COVID-19 pandemic is currently ongoing. Presently, due to the unavailability of a definitive vaccine to decrease its acquiring, it’s essential to understand its transmissibility in the community by undetected cases to control its transmission. This study aims to study this context using mathematical modelling. METHODS: A COVID-19 transmission model was framed that estimated the basic reproduction number [Formula: see text] (a measurement of disease risk) using the next-generation method. It explored the contribution of exposed and infected (detected and undetected) individuals, and environmental pathogen to the overall risk of infection spreading, utilizing the publicly reported data of this infection in Maharashtra between March 22, 2020, and May 4, 2020. A sensitivity analysis was performed to study the effect of a rising number of undetected cases to [Formula: see text] . RESULTS: The estimated basic reproduction number is [Formula: see text] , which increases rapidly with the rise in the undetected COVID-19 cases. Although the exposed individuals made the largest contribution to infection transmission ([Formula: see text] ), the contaminated environment also played a significant role. CONCLUSIONS: It is crucial to identify the individuals exposed and infected to COVID-19 disease and isolate them to control its transmission. The awareness of the role of fomites in infection transmission is also important in this regard.