JMIR Publications

ABSTRACT

Background:

During 2021 several new variants of the SARS-CoV-2 virus appeared with both increased levels of transmissibility and virulence with respect to the original wild variant. The Delta (B.1.617.2) variation, first seen in India, dominates COVID-19 infections in several large countries including the United States and India. Most recently, the Lambda variant of interest with increased resistance to vaccines has spread through much of South America.

Objective:

This research explores the degree to which new variants of concern 1) generate spikes and waves of fluctuations in the daily case fatality rates (CFR) across countries in several regions in the face of increasing levels of vaccination of national populations and 2) may increase the vulnerability of persons with certain co-morbidities.

Methods:

This study uses new, openly available, epidemiological statistics reported to the relevant national and international authorities for countries across the Americas, Europe, Africa, Asia and the Middle East. Daily CFRs and correlations of fatal COVID-19 infections with potential co-factors are computed for the first half of 2021 that has been dominated by the wide spread of several “variants of concern” as denoted by the World Health Organization.

Results:

The analysis yields a new quantitative measure of the temporal dynamics of mortality due to SARS-CoV-2 infections in the form of variations of a proxy case fatality rate compared on a country to-country basis in the same region. It also finds minimal variation of correlation between the co-factors based on WHO data and on the average apparent case fatality rate.

Conclusions:

The proxy for the daily case fatality rate computed over a smoothed distribution of deaths attributed to COVID-19 infections provides a useful metric to track the national dynamics of the spread of SARS-CoV-2 variants of concern overlaid with a country’s vaccination implementation program. The increases in daily proxy CFR in the US and Germany correspond in timing with the rapid spread of the Delta variant and support the characterization of Delta as being more virulent than the original wild strain of SARS-CoV-2. The new variants of concern lead to minimal quantitative differences with the conclusion of Ref. [2] that most commonly cited co-morbidities do not in and of themselves increase the risk of serious (and possibly fatal) consequences of SARS-CoV-2 infections.