Robust and fragile determinants of the infection and case fatality rates of Covid-19: international cross-sectional evidence

ABSTRACT

An attempt is made to identify the factors that can explain inter-country differences in the severity of Covid-19, measured by the infection and case fatality rates. To circumvent the problem of the sensitivity of the results with respect to the selected set of explanatory variables, extreme bounds analysis (EBA) is applied to a cross-sectional sample of 154 countries. The results show that the infection and fatality rates depend on different factors, except for the number of tests, which is a robust determinant of both. An interesting result is that the infection rate depends on urban population rather than the overall population density. Another interesting result is that the fatality rate depends on the age structure of the population and population density but not on the percentage of urban population.

KEYWORDS:

• Covid-19
• infection rate
• case fatality rate
• extreme bounds analysis
• cumulative density function

JEL CLASSIFICATION:

• I10
• I19

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

¹ The simplest epidemiological model is the SIR model, which belongs to the family of compartmental models used for the mathematical representation of infectious diseases. According to this model, the population is assigned to three compartments: S (susceptible), I (infected) and R (recovered). The model is represented by three differential equations explaining the growth rates over time of S, I and R. In this model, I is the number of cases, whereas the number of deaths is the difference between I and R.

² See, for example, the critique of Leamer’s EBA presented by McAleer, Pagan, and Volker (1985) and the reply of Cooley and LeRoy (1986).

³ For a discussion of the debate on EBA, see Moosa (2017).

⁴ https://www.ghsindex.org/

⁵ Distinction can be made between the case fatality rate and the population fatality rate (deaths per million of the population).

⁶ As on 13 May, 74% of the people who died by Covid-19 in New York City were over 65. More than 22% were between 45 and 64. Only 0.06% were 0–17 years old. https://www.worldometers.info/coronavirus/coronavirus-age-sex-demographics/.