Characteristics and Outcomes of Patients Infected With Conventional Strains and the Alpha Variant of Severe Acute Respiratory Syndrome Coronavirus 2

Background There is concern that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants may have higher infectivity and virulence than does the original strain. We compared disease severity between patients infected with conventional strains of SARS-CoV-2 and those infected with the alpha variant. Methods The study included patients with SARS-CoV-2 infection confirmed in Fukui Prefecture between March 12, 2020, and May 12, 2021. They were grouped into 4 phases based on fluctuations in the number of notifications. Data analysis was performed using EZR version 1.41 and BellCurve for Excel version 3.20. Results The analysis included 963 patients with SARS-CoV-2 infection, 346 of whom were infected with the alpha variant. In stratified analyses, patients infected with the alpha variant did not differ significantly from patients infected with conventional strains in terms of disease severity or mortality. Among individuals with SARS-CoV-2 infection, risk factors for pneumonia included infection with the alpha variant, older age, and male sex. Conclusions Infection with the alpha variant was associated with a higher frequency of pneumonia, but not with increased disease severity or mortality.