Airborne virus shedding of the alpha, delta, omicron SARS‐CoV‐2 variants and influenza virus in hospitalized patients

Abstract

AbstractAirborne transmission is an important transmission route for the spread of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Epidemiological data indicate that certain SARS‐CoV‐2 variants, like the omicron variant, are associated with higher transmissibility. We compared virus detection in air samples between hospitalized patients infected with different SARS‐CoV‐2 variants or influenza virus. The study was performed during three separate time periods in which subsequently the alpha, delta, and omicron SARS‐CoV‐2 variants were predominant. In total, 79 patients with coronavirus disease 2019 (COVID‐19) and 22 patients with influenza A virus infection were included. Collected air samples were positive in 55% of patients infected with the omicron variant in comparison to 15% of those infected with the delta variant (p < 0.01). In multivariable analysis, the SARS‐CoV‐2 omicron BA.1/BA.2 variant (as compared to the delta variant) and the viral load in nasopharynx were both independently associated with air sample positivity, but the alpha variant and COVID‐19 vaccination were not. The proportion of positive air samples patients infected with the influenza A virus was 18%. In conclusion, the higher air sample positivity rate of the omicron variant compared to previous SARS‐CoV‐2 variants may partially explain the higher transmission rates seen in epidemiological trends.