Distracted multinomial model for corona screening at entry ports

Ramalingam Shanmugam


Background: On 24 January 2020, 1287 corona cases were noticed in Wuhan, China, causing 41 deaths. Its incubation period is at least 14 days. Now, this deadly virus has spread to other foreign countries. The prevalence of corona cases is changing daily. See for daily reports. The corona cases are mystic and nightmare to the public, health professionals, and governing agencies globally.

Methods: The Center for Disease Control (CDC) compiled in their webpage ( the number of confirmed, number of healthy, and the number of pending cases at the port of entries in United States of America (USA). These numbers are perhaps under-estimates because of inappropriate diagnostics and imprecise incubation period. To resolve the under estimating, this article, introduces a distracted multinomial model to refine the imprecise corona screening process and interpret the probability of detecting a corona case in US entry gates.

Results: An alternate expression (2) for the correlation between the corona ill and corona free cases at the USA ports of entry reveals that it was rising since 31st January 2020, reached its maximum on 5th February 2020, then declined to hit a bottom on 7th February 2020 only to rise again.

Conclusions: Most desirable is an accurate predictability of a traveller with the corona virus at the portal entry to minimize its spread. To make such prediction, a regression is necessary with involvement of covariates like age, body’s immunity level, comorbidity, and precise understanding of its incubation period. The model in this article is the starting point for further future research work.


Conditional prediction, Inappropriate diagnostic, Multinomial frequency trend, Model, Probability indices, Prevalence of corona cases, Under-estimate

Full Text:



Habibzadeh P, Stoneman EK. The novel coronavirus: a bird’s eye view. Int J Occup Environ Med. 2020 Mar 27;11(2 April):1921-65.

Zhang Y. The Novel Coronavirus Pneumonia Emergency Response Epidemiology Team. The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19) – China, 2020. Available at:, China CDC Weekly. 2.

Zhou P, Yang XL, Wang XG, Hu B, Zhang L, Zhang W, et al. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature. 2020 Mar;579(7798):270-3.

Heymann DL, Shindo N. COVID-19: what is next for public health?. Lancet. 2020 Feb 22;395(10224):542-5.

2019 Novel Coronavirus. Centers for Disease Control and Prevention. Available at: Accessed 11 February 2020.

Symptoms of Novel Coronavirus (2019-nCoV) | CDC, U.S. Centers for Disease Control and Prevention (CDC). Available at: Accessed 10 February 2020.

Prevention and Treatment, Centers for Disease Control and Prevention (CDC). Available at: Accessed 9 August 2019.

Prevention and Treatment. Centers for Disease Control and Prevention (CDC). Available at: Accessed 9 August 2019.

Updates on Wuhan Coronavirus (2019-nCoV) Local Situation, Available at:

National Health Commission (NCP). National Health Commission of the People's Republic of China. Available at: Accessed 10 February 2020.

Shim E, Tariq A, Choi W, Lee Y, Chowell G. Transmission potential and severity of COVID-19 in South Korea. Int J Infect Dis. 2020 Mar 18;93:339-44.

Wilder-Smith A, Freedman DO. Isolation, quarantine, social distancing and community containment: pivotal role for old-style public health measures in the novel coronavirus (2019-nCoV) outbreak. J Travel Medi. 2020 Mar;27(2):20.

Dell'Omodarme M, Prati MC. The probability of failing in detecting an infectious disease at entry points into a country. Statist Medi. 2005 Sep 15;24(17):2669-79.

Shanmugam R, Chattamvelli R. Statistics for scientists and engineers. John Wiley Press, Hoboken, NJ; 2016.

Stuart A, Ord JK. Kendall’s Advanced Theory of Statistics. In: Kendall MG, Stuart A, Ord JK. Volume 1. Oxford University Press, London. 2015.