Examining COVID-19 mortality inequalities across 169 countries: Insights from the COVID-19 mortality inequality curve (CMIC) and Theil index analysis

Background

The COVID-19 pandemic has highlighted global disparities in health outcomes, with mortality driven by pre-existing comorbidities, demographic vulnerabilities, and systemic socioeconomic inequalities. These factors underscore the need for evidence-based policies to address health inequities and strengthen system resilience.

Objective

This study quantifies COVID-19 mortality disparities across 169 countries, focusing on obesity, age, and income dimensions, to inform equitable and effective policy interventions.

Methods

Using publicly available datasets, the COVID-19 Mortality Inequality Curve (CMIC) and Index (CMII) were applied to measure disparities, while the Theil Index decomposed them into within- and between-group components. Mortality data were analyzed at three time points—December 2020, August 2021, and February 2022—to capture the effects of vaccination campaigns.

Results

The Theil Index revealed significant reductions in mortality inequality among countries with lower obesity rates (from 1.43 to 0.80) and older populations (from 0.95 to 0.54), reflecting the impact of targeted vaccination efforts. However, income-based disparities showed limited improvement (Theil Index: 0.61 to 0.54), emphasizing persistent inequities in healthcare access. High-income countries achieved the most significant reductions in inequality due to early and widespread vaccination.

Conclusions

Tailored health policies prioritizing equitable vaccine distribution, data harmonization, and targeted interventions for obesity and age-related vulnerabilities are critical for reducing disparities and strengthening health system resilience during global crises.