Age-Related Morbidity and Mortality among Patients with COVID-19

Abstract

On March 11, 2020, the World Health Organization declared coronavirus disease (COVID-19), caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a pandemic. During the COVID-19 pandemic, an age-associated vulnerability in the burden of disease has been uncovered. Understanding the spectrum of illness and the pathogenic mechanism of the disease in a vulnerable population is critical, especially during the pandemic. Herein, we reviewed published COVID-19 epidemiology data from several countries to identify any consistent trends in the relationship between age and COVID-19-associated morbidity or mortality. We also reviewed the literature for studies explaining the difference in the host response to SARS-CoV-2 infection according to age. The insights from these data will be useful in determining the treatment policies and preventive measures of COVID-19.

Keywords: Age; COVID-19; Morbidity; Mortality; Pandemic.

Figure 1. Age-related risk of death from coronavirus disease (COVID-19), influenza, and overall causes. (A) Case fatality rate (CFR, death/laboratory confirmed cases) of COVID-19 in China, Korea (accumulated data until May 10, 2020), and Italy (as of March 26, 2020). (B) Death per 100,000 from COVID-19 in New York City (as of May 11, 2020) and United Kingdom (as of May 8, 2020). (C) Death per 100,000 from influenza and pneumonia in interpandemic years (dashed line 1911 - 1917) and pandemic year (solid line 1918) in the United Sates. Adapted from Taubenberger et al [10]. (D) All-cause mortality and cardiovascular mortality (death per 100,000) according to age in Korea, 2018. Data were extracted from “Cause-of-death statistics in 2018,” released by Statistics Korea [15].

Figure 2. Case rate (cases per 100,000) of COVID-19 according to age in different regions. (A) New York City (as of May 11, 2020). (B) Korea (as of May 10, 2020).

Figure 3. Relative illness ratio by 5-year age groups. Relative Illness Ratio (RIR) is a measure of morbidity calculated according to the following formula as the share of COVID-19 cases in each age group with regard to the total number of morbidity cases divided by the share of the population in the same age group. RIRi = (Ccovidi/∑iCcovidi)(Pi∑iPi), where COVID is the estimated number of cases of COVID-19 in age group ἰ, and P is the population in the same age group. A value above 1 indicates that there is a higher proportion of cases in the age group relative to other age groups, after considering differences in the size of the population. Adapted from Natale et al. [17].