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Malin Alsved

Malin Alsved

Postdoctoral Fellow

Malin Alsved

SARS-CoV-2 in aerosol particles exhaled from COVID-19 infected patients during breathing, talking and singing


  • Malin Alsved
  • David Nygren
  • Patrik Medstrand
  • Sara Thuresson
  • Anders Widell
  • Carl-Johan Fraenkel
  • Jakob Löndahl

Summary, in English

In the beginning of the COVID-19 pandemic, several super spreader events occurred during singing in choirs, which lead to an increased attention to airborne transmission of SARS-CoV-2, the virus causing COVID-19. Since then, aerosol generation from singing has been studied in more detail, however, only from healthy subjects. In this study, we collected aerosol particles in the exhaled breath of 40 COVID-19 infected patients during breathing, talking and singing, respectively, and analysed the samples for detection of SARS-CoV-2.

Patients that were contacted by the COVID-19 testing service due to a positive test result were asked to volunteer for the study. A team of researchers drove a small truck hosting a mobile laboratory to the home address of the patient to perform exhaled breath aerosol collection using a condensational particle collector (BioSpot, Aerosol Devices) and a two-stage cyclone sampler (NIOSH bc-251, Tisch Environmental). Samples were collected for 10 min each when the patient was breathing, talking and singing, respectively.

All samples were stored at -80°C until RNA extraction and analysis by reverse transcription quantitative polymerase chain reaction (RT-qPCR) targeting the N-gene.

A first screening of air samples collected with the BioSpot showed that SARS-CoV-2 could be detected in the exhaled aerosols from three of nine patients during singing or talking. Two of these samples contained 103 and 104 viral RNA copies, corresponding to a viral emission rate of approximately 4 and 25 viruses per second, respectively. Samples from the remaining 31 patients are to be analysed during the spring. We hope to contribute to quantifying and understanding the Covid-19 transmission via the airborne route.

This study was approved by the Swedish Ethics Review Authority (2020-07103). This work was supported by AFA Insurances and the Swedish Research Council FORMAS.


  • Ergonomics and Aerosol Technology
  • Metalund
  • NanoLund: Center for Nanoscience
  • Infection Medicine (BMC)
  • Translational infection medicine
  • EpiHealth: Epidemiology for Health
  • Clinical Virology, Malmö
  • Clinical Microbiology, Malmö

Publishing year




Document type

Conference paper: abstract


  • Infectious Medicine

Conference name

American Association for Aerosol Research Annual Conference

Conference date

2021-10-18 - 2021-10-22

Conference place

United States



Research group

  • Translational infection medicine
  • Clinical Virology, Malmö
  • Clinical Microbiology, Malmö