DOI: http://dx.doi.org/10.18203/2394-6040.ijcmph20212574

Epidemiological philosophy of pandemics

Tareef Fadhil Raham

Abstract


Background: During  the COVID-19 pandemic, clinicians have struggled to understand why case fatality rates vary among countries. The role of clusters of infections in COVID-19 severity is well known before, furthermore the case overload was attributed to increased COVID-19 mortality in certain locations. The background theory in this study was the  already existing evidence that an increased viral load (density of infection) leads to more fatalities. The aim of this study was to find the correlation between high number of cases and high mortality (MR) in different countries and to find the correlation of MR with case fatality rate (CFR).

Methods: We chose thirty-one countries with testing coverage levels of >400,0000 tests/M and populations greater than 1 million inhabitants. We used ANOVA regression analyses to test the associations.

Results: There was a very highly significant correlation between MR and the total number of cases/million population inhabitants (M) (p=0.0000). The CRF changed with a change in the MR. A very high positive influence of the COVID-19 MR on the CFR (p= 0.0000).

Conclusions: Increased number of cases per million inhabitants is associated with increased MR. Increased MR is associated with increased CFR. These findings explain variable mortality rates in relation to CFR and to the number of cases/M. This evidence gives us an idea of the behavior of epidemics in general. This  will help in the development of infection control policies.


Keywords


COVID-19, CFR, MR, Pandemic, Epidemic

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References


Damme WV, Dahake R, Pas RVD, Vanham G, Assefa Y. COVID-19: Does the infectious inoculum dose-response relationship contribute to understanding heterogeneity in disease severity and transmission dynamics? Med Hypotheses. 2021;146:110431.

Han A, Czajkowski LM, Donaldson A, Baus HA, Reed SM, Athota RS, et al. A dose-finding study of a wild-type influenza A(H3N2) Virus in a healthy volunteer human challenge model. Clin Infect Dis. 2019;69(12):2082-90.

Watson JM, Francis JN, Mesens S, Faiman GA, Makin J, Patriarca P, et al. Characterisation of a wild-type influenza (A/H1N1) virus strain as an experimental challenge agent in humans. Virol J. 2015;12:13.

Aaby P. Assumptions and contradictions in measles and measles immunization research: Is measles good for something? Soc Sci Med. 1995;41(5):673-86.

Cresswell F, Waters L, Briggs E, Fox J, Harbottle J, Hawkins D, et al. UK guideline for the use of HIV post-exposure prophylaxis following sexual exposure, 2015. Int J STD AIDS. 2016;27(9):713-38.

Saini D, Hopkins GW, Seay SA, Chen C, Perley CC, Click EM, et al. Ultra-low dose of Mycobacterium tuberculosis aerosol creates partial infection in mice. Tuberculosis (Edinb). 2012;92(2):160-5.

Fennelly KP, Jones-López EC. Quantity and quality of inhaled dose predicts immunopathology in tuberculosis. Front Immunol. 2015;6:313.

Yershov AL, Jordan BS, Guymon CH, Dubick MA. Relationship between the inoculum dose of Streptococcus pneumoniae and pneumonia onset in a rabbit model. Eur Respir J. 2005;25(4):693-700.

Asabe S, Wieland SF, Chattopadhyay PK, Roederer M, Engle RE, Purcell RH, et al. The size of the viral inoculum contributes to the outcome of hepatitis B virus infection. J Virol. 2009;83(19):9652-62.

King NJC, Getts DR, Getts MT, Rana S, Shrestha B, Kesson AM. Immunopathology of flavivirus infections. Immunol. Immunol Cell Biol. 2007;85(1):33-42.

Al-Abdely HM, Midgley CM, Alkhamis AM, Abedi GR, Lu X, Binder AM, et al. Middle East respiratory syndrome coronavirus infection dynamics and antibody responses among clinically diverse patients, Saudi Arabia. Emerg Infect Dis. 2019;25(4):753-66.

Rouse BT, Sehrawat S. Immunity and immunopathology to viruses: what decides the outcome? Nat Rev Immunol. 2010;10(7):514-26.

Gandhi M, Beyrer C, Goosby E. Masks reduce viral inoculum of SARS-CoV2. J Gen Intern Med. 2021;36:1124-5.

Giattino C.How epidemiological models of COVID-19 help us estimate the true number of infections. Our World in Data. Available at: https://ourworldindata.org/covid-models. Accessed on 24 August 2020.

Meyerowitz-Katz G, Merone L. A systematic review and meta-analysis of published research data on COVID-19 infection fatality rates. Int J Infect Dis. 2020;101:138-48.

Inga H, Caroline B. Wrong but useful: what COVID-19 epidemiologic models can and cannot tell us. N Engl J Med. 2020;383:303-5.

WHO. Fact sheet: Estimating mortality from COVID-19, 2020. Available at: https://www.who.int/publications/i/item/WHO-2019-nCoV-Sci-Brief-Mortality-2020.1. Accessed on 17 April 2021.

The Diamond Princess-estimating the Covid-19 case fatality rate in a closed system. Viable opposition. Available at: https://viableopposition.blogspot.com/2020/04/the-diamond-princess-estimating-covid.html. Accessed on 8 April 2020.

Russell TW, Hellewell J, Jarvis CI, Zandvoort KV, Abbott S, Ratnayake R, et al. Estimating the infection and case fatality ratio for COVID-19 using age-adjusted data from the outbreak on the Diamond Princess cruise ship. MedRxiv. 2020.

Rajgor DD, Lee MH, Archuleta S, Bagdasarian N, Quek SC. The many estimates of the COVID-19 case fatality rate. Lancet. 2020;20(7):776-7.

CDC. Fact sheet: COVID-19 pandemic planning scenarios, 2021. Available at: http://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scenarios.html. Accessed on 17 April 2021.

Hwang DH, Han JW, Choi KM, Shin KM, Kim DS. Expression of toll-like receptor-2 on the peripheral blood monocytes in Kawasaki disease patients. Korean J Pediatr. 2005;48(3):315-20.

Chen KYH, Messina N, Germano S, Bonnici R, Freyne B, Cheung M, et al. Innate immune responses following Kawasaki disease and toxic shock syndrome. PLoS One. 2018;13(2):0191830.

Nishio H, Kanno S, Onoyama S, Ikeda K, Tanaka T, Kusuhara K, et al. Nod1 ligands induce site-specific vascular inflammation. Arterioscler Thromb Vasc Biol. 2011;31(5):1093-9.

Kim KY, Kim DS. Recent advances in Kawasaki disease. Yonsei Med J. 2016;57(1):15-21.

Rowley AH. Understanding SARS-CoV-2-related multisystem inflammatory syndrome in children. Nat Rev Immunol. 2020;20(8):453-4.

Lowe A, Chang DD, Creek G. Multiple fatalities in a family cluster of COVID-19 with acute respiratory distress syndrome. Ochsner J. 2020;20(2):134-8.

Maugeri A, Barchitta M, Basile G, Agodi A. Different patterns of the SARS-CoV-2 epidemic across italian regions: a hierarchical clustering on principal components approach. Res Square. 2020.

CDC. Fact sheet: Excess deaths associated with COVID-19, 2021. Available at: https://www.cdc.gov/nchs/nvss/vsrr/covid19/excess_deaths.htm. Accessed on 17 April 2021.

Morens D. Measles in Fiji, 1875: thoughts on the history of emerging infectious diseases. Pac Health Dialog. 1981:1(5);119-28.

Shanks GD, Lee S, Howard A, Brundage JF. Extreme mortality after first introduction of measles virus to the polynesian Island of Rotuma 1911. Ame J Epidemiol. 2011;173(10):1211–22.

Noymer A, Garenne M. The 1918 influenza epidemic's effects on sex differentials in mortality in the United States. Popul Dev Rev. 2000;26(3):565-81.

Crosby A. America's forgotten pandemic: the influenza of 1918. 2nd ed. Cambridge: Cambridge University Press; 1989.