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Assessing relative COVID-19 mortality during the second wave: a prospective Swiss population-based study
Sandra Siegfried1, Matthias Bopp1, Huldrych Günthard2,3
1Institut für Epidemiologie, Biostatistik und Prävention, Universität Zürich, Zürich, Switzerland.
BMJ Open
|October 5, 2021
Summary
The risk of death from COVID-19 in Switzerland
Area of Science:
- Epidemiology
- Public Health
- Infectious Diseases
Background:
- During the first wave of COVID-19 in Switzerland, relative mortality for infected individuals was at least eight times higher than in the general population.
- Understanding mortality patterns during subsequent waves is crucial for public health interventions.
Purpose of the Study:
- To assess sex-specific and age-specific relative mortality associated with SARS-CoV-2 diagnosis during the second COVID-19 wave in Switzerland.
- To compare COVID-19 mortality during the second wave with the first wave.
Main Methods:
- Prospective population-based study analyzing data from October 1 to December 31, 2020.
- Utilized proportional hazards models to estimate sex-specific and age-specific mortality rates and probabilities of death within 60 days.
- Matched confirmed SARS-CoV-2 diagnoses and deaths with all-cause mortality data from the Swiss general population (2018).
Main Results:
- Individuals testing positive for SARS-CoV-2 faced at least a sixfold increased risk of death compared to the general population.
- The hazard ratio for death was higher for men (1.40) and increased with age (1.01 per year).
- COVID-19 mortality was reduced by at least 20% in the second wave compared to the first wave.
Conclusions:
- Mortality patterns, with higher risks for men and older individuals, were consistent between the first and second COVID-19 waves.
- Absolute and relative COVID-19 mortality were lower during the second wave in the fall compared to the first wave in spring.
- The study highlights the persistent elevated mortality risk associated with SARS-CoV-2 infection, particularly in men and the elderly.
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