Airborne route and bad use of ventilation systems as non-negligible factors in SARS-CoV-2 transmission

Med Hypotheses. 2020 Aug:141:109781. doi: 10.1016/j.mehy.2020.109781. Epub 2020 Apr 25.


The world is facing a pandemic of unseen proportions caused by a corona virus named SARS-CoV-2 with unprecedent worldwide measures being taken to tackle its contagion. Person-to-person transmission is accepted but WHO only considers aerosol transmission when procedures or support treatments that produce aerosol are performed. Transmission mechanisms are not fully understood and there is evidence for an airborne route to be considered, as the virus remains viable in aerosols for at least 3 h and that mask usage was the best intervention to prevent infection. Heating, Ventilation and Air Conditioning Systems (HVAC) are used as a primary infection disease control measure. However, if not correctly used, they may contribute to the transmission/spreading of airborne diseases as proposed in the past for SARS. The authors believe that airborne transmission is possible and that HVAC systems when not adequately used may contribute to the transmission of the virus, as suggested by descriptions from Japan, Germany, and the Diamond Princess Cruise Ship. Previous SARS outbreaks reported at Amoy Gardens, Emergency Rooms and Hotels, also suggested an airborne transmission. Further studies are warranted to confirm our hypotheses but the assumption of such way of transmission would cause a major shift in measures recommended to prevent infection such as the disseminated use of masks and structural changes to hospital and other facilities with HVAC systems.

Keywords: Aerosol; COVID-19; HVAC; SARS-Cov-2; Ventilation.

MeSH terms

  • Aerosols
  • Air Conditioning / adverse effects
  • Air Conditioning / instrumentation
  • Air Conditioning / methods
  • Air Microbiology*
  • Air Pollution, Indoor
  • Betacoronavirus / isolation & purification*
  • COVID-19
  • Coronavirus Infections / prevention & control
  • Coronavirus Infections / transmission*
  • Cross Infection / transmission
  • Environment, Controlled*
  • Equipment Contamination
  • Equipment Design
  • Equipment Failure
  • Fomites / virology
  • Heating / adverse effects
  • Heating / instrumentation
  • Heating / methods
  • Humans
  • Legionnaires' Disease / epidemiology
  • Legionnaires' Disease / transmission
  • Models, Biological
  • Pandemics* / prevention & control
  • Pneumonia, Viral / prevention & control
  • Pneumonia, Viral / transmission*
  • SARS-CoV-2
  • Sanitary Engineering / instrumentation
  • Severe Acute Respiratory Syndrome / epidemiology
  • Severe Acute Respiratory Syndrome / transmission
  • Sewage / virology
  • Ventilation* / instrumentation
  • Ventilation* / methods


  • Aerosols
  • Sewage