In a recent study published in BMJ Global HealthResearchers compare coronavirus disease 2019 (COVID-19) excess mortality rates in 183 countries.
Learn: Assessment of the Global Health Security Index as a predictor of COVID-19 excess mortality, standardized for under-reporting and age structure. Photo credit: ETAJOE / Shutterstock.com
COVID-19, an infectious viral disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), quickly became the leading cause of death worldwide after the pandemic began in March 2020.
Although most countries are implementing various measures to reduce SARS-CoV-2 transmission, many of these measures have been disjointed around the world. Therefore, examining pandemic preparedness metrics at the country level is crucial to ensure nations around the world can take effective countermeasures in the future.
In addition to responsiveness, previous studies have shown that many countries around the world have been disproportionately affected by COVID-19 due to the unique age structure of their populations.
For example, countries with a higher proportion of older people were more susceptible to severe COVID-19 illness. Likewise, each country’s surveillance efforts identified its underlying risk for severe COVID-19.
About the study
In the present study, researchers examine country-specific associations between pandemic preparedness measures and age-standardized COVID-19 excess mortality in 183 countries.
During the COVID-19 pandemic, comparative mortality rates (CMRs) were calculated to account for country-level surveillance capacities and differences in age structure.
CMRs are a widely used form of indirect age standardization in epidemiological studies. These values use an age structure of mortality from a reference country, in this case the United States, to compare mortality between countries and compare COVID-19 outcomes.
Mortality data from the Institute for Health Metrics and Evaluation (IHME) were used to model estimates for excess mortality from COVID-19 between January 1, 2020 and December 31, 2021. The COVID-19 Death Demographics database was used to compile age and specific COVID-19 mortality data to facilitate CMR calculation.
Direct age standardization requires extensive age-stratified data on COVID-19 mortality, which is currently unavailable for most countries. For the current study, calculated age-stratified aggregate mortality rates for the US and United Nations (UN) population sizes were used to determine age ranges.
Country-specific CMRs were also determined, with a CMR greater than or less than one representing an increase or decrease in mortality compared to the reference country.
National preparedness efforts were assessed using the Global Health Security (GHS) Index. This index has six preparedness categories, 37 indicators, and a subset of sub-indicators that help quantify a country’s potential to prevent an infectious disease outbreak. Data on the GHS index are publicly available for 195 countries, which the researchers used for a priori identification for analysis.
Pearson’s R correlations and multiple linear regression analyzes were used to assess the relationship between GHS readings and COVID-19 CMRs. Additionally, bivariate regression models were used to assess each relationship independently of the other GHS indicators.
Confidence intervals (CIs) with robust standard errors were calculated and adjusted to account for testing multiple hypotheses using a Bonferroni correction. The coefficients and corresponding CIs represented CMR variations associated with differences in five-point GHS index measures. A series of sensitivity analyzes was also performed to determine the robustness of these results.
There remains a lack of comparable data from countries studying the outcomes of COVID-19. Therefore, detailed age-specific COVID-19 mortality rates are only available for 22 countries. Likewise, data on COVID-19 deaths is underreported due to global differences in the performance of key statistics.
The GHS index was used as a predictor of the number of deaths due to COVID-19. After accounting for higher GHS index scores associated with lower CMRs for excess COVID-19 mortality, implementing efforts to prepare for and respond to pandemics before they occur could be effective in reducing mortality from similar global health emergencies.
Three GHS categories of prevention, detection and response reduced the number of COVID-19 deaths. Prevention approaches, for example, reduced the number of COVID-19 deaths by reducing other infectious disease outbreaks. In addition, immunization capacity may have minimized vaccine-preventable deaths and created an infrastructure for successful immunization programs.
The detection capabilities of the laboratories that conduct case-based investigations have reduced the number of COVID-19 deaths. Likewise, emergency preparedness and responses, such as non-pharmacological interventions (NPIs), resulted in a reduction in the number of COVID-19 deaths.
Even during a pandemic, cross-border agreements proved advantageous. One example is countries in the European Union that have opened their borders to healthcare workers and those seeking medical assistance to share the burden of the pandemic.
The risk environment, a category of the GHS Index, had the most consistent association with excess COVID-19 mortality. Although the US ranked highest in the GHS Index out of 57 high-income countries, it ranked 30th in the risk environment assessment.
The study analyzes also provided evidence that social and government support is critical in responding to a health crisis. Future studies should therefore examine the role of other country-level capacities unrelated to excess COVID-19 deaths, including health care and intervention planning.
The associations between pandemic preparedness capacities and excess mortality dropped to zero using WHO and The Economist data. The WHO, the Economist, and the Institute for Health Metrics and Evaluation (IHME) use different sets of covariates; For example, in countries with GHS values below 40, such as in various African countries, COVID-19 deaths were undercounted by a factor of 10.
The GHS Index is an inventory of the resources and plans available in each country to deal with a health crisis. The current analysis showed that greater health security capacities, as measured by the GHS index, reduce excess COVID-19 mortality. Investments in health systems could thus influence the consequences of a pandemic.
All countries need a well-established response infrastructure to deal with a health crisis and an accessible, equitable and competitive health system to detect outbreaks. In the future, building, maintaining and measuring health security capacities could effectively mitigate the impact of infectious disease threats.