Mutual relationships between SARS-CoV-2 test numbers, fatality and morbidity rates

Area of Science:

• Epidemiology
• Public Health
• Biostatistics

Background:

• SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) testing rates are a modifiable factor influencing pandemic outcomes.
• Unlike demographic or comorbidity factors, testing numbers can be adjusted by policymakers based on pandemic status and resource availability.
• Understanding the relationship between testing volume and disease impact is crucial for effective public health interventions.

Purpose of the Study:

• To probabilistically determine the relationship between the number of SARS-CoV-2 tests conducted and associated morbidity and fatality rates.
• To identify specific ranges of testing numbers that are most impactful for pandemic management and control.

Main Methods:

• Statistical analysis of 1058 monthly observations from 107 countries (March 2020 - January 2021).
• Utilized monthly test numbers, prior month's reported cases, and per capita morbidity/mortality rates.
• Employed moving percentiles, power law fitting, and three-segment piecewise linear approximation (Theil Sen trend lines) to analyze probabilistic relationships.

Main Results:

• A power law relationship was identified between SARS-CoV-2 testing rates and morbidity/fatality rates, well-approximated by three distinct Theil Sen trend lines.
• Significant negative correlations (Spearman rho and Kendall tau-b, p < 0.002) were observed between testing numbers and morbidity/fatality rates across all identified ranges.
• The study identified specific ranges of test numbers with varying degrees of importance (ABC classification) for pandemic management.

Conclusions:

• The number of SARS-CoV-2 tests significantly correlates with morbidity and fatality rates, following predictable patterns.
• Defined critical ranges of testing numbers are essential for effective pandemic control strategies.
• Recommendations for optimizing SARS-CoV-2 testing strategies are provided based on the identified relationships.