Abstract

SARS-CoV-2 variants evolve to balance immune evasion and airborne transmission, yet the mechanisms remain unclear. In hamsters, first-wave, Alpha, and Delta variants transmitted efficiently via aerosols. Alpha emitted fewer viral particles than first-wave virus but compensated with a lower infectious dose (ID 50 ). Delta exhibited higher airborne emission but required a higher ID 50 . A fall in airborne emission of infectious Delta virus over time after infection correlated with a decrease in its infectivity to RNA ratio in nasal wash and a decrease in contagiousness to sentinel animals. Omicron subvariants (BA.1, EG.5.1, BA.2.86, JN.1) displayed varying levels of airborne transmissibility, partially correlated with airborne emissions. Mutations in the non-spike genes contributed to reduced airborne transmissibility, since recombinant viruses with spike genes of BA.1 or JN.1 and non-spike genes from first-wave virus are more efficiently transmitted between hamsters. These findings reveal distinct viral strategies for maintaining airborne transmission. Early assessment of ID50 and aerosolized viral load may help predict transmissibility of emerging variants.

Rights

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Cite as

Zhou, J., Sukhova, K., Frise, R., Baillon, L., Brown, J., Peacock, T., Furnon, W., Cowton, V., Patel, A., Palmarini, M. & Barclay, W. 2025, 'SARS-CoV-2 variants retain high airborne transmissibility by different strategies', npj Viruses, 3, article no: 39. https://doi.org/10.1038/s44298-025-00120-1

Downloadable citations

Download HTML citationHTML Download BIB citationBIB Download RIS citationRIS
Last updated: 09 May 2025
Was this page helpful?