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Assessing the age specificity of infection fatality rates for COVID-19: systematic review, meta-analysis, and public policy implications

Our take —

This systematic review and meta-analysis aims to describe age-specific infection fatality ratio (IFRs) for COVID-19, which includes both symptomatic and asymptomatic infected individuals. IFR increased exponentially as age increased, with rates of 0.002% at age 10 years, 0.01% at age 25 years, 0.4% at age 55 years, 1.4% at age 65 years, 4.6% at age 75 years, 15% at age 85 years, and more than 25% for ages 90 years and above. The studies included were limited to high income settings and may not represent other settings. The results of this meta-analysis suggest that variation in IFR across locations may reflect the population composition and differences in the extent to which older age groups were exposed to COVID-19.

Study design

Other

Study population and setting

This systematic review and meta-analysis aims to describe age-specific infection fatality ratios (IFRs) for COVID-19. The systematic review utilized MedRxiv, Medline, PubMed, Google Scholar, and EMBASE to identify articles published before September 18, 2020. A total of 27 articles were included in the meta-analysis, which were categorized based on sampling strategies including representative samples, convenience samples, and comprehensive tracing programs. Data from 28 locations were included in the meta-regression analysis, and data from 6 locations were used for out-of-sample analysis.

Summary of Main Findings

The IFR was lowest for children and young adults, with 0.002% at age 10 years and 0.01% at age 25 years. However, IFR rises to 0.4% at age 55 years, 1.4% at age 65 years, 4.6% at age 75 years, 15% at age 85 years, and more than 25% for ages 90 years and above. The regression analysis observed an exponential relationship between age and IFR for COVID-19.

Study Strengths

This study aimed to estimate IFR while carefully considering the sampling methods for data collection across studies. The authors conducted several sensitivity analyses to assess data and test assumptions.

Limitations

The studies included in this meta-analysis only include higher income settings, defined as advanced economies, based on current membership in the Organization for Economic Cooperation and Development (OECD). Therefore, results may not be transportable to lower income settings. Additionally, the results do not describe within age category variation of IFRs, which may have been helpful especially for children under 10 years of age.

Value added

This study aimed to estimate IFR to describe the severity of COVID-19 infection across a population and assess the relationship between IFR and age. The methods considered the sampling methods for data collection across studies in an attempt to accurately capture IFR across settings.

This review was posted on: 28 January 2021