Health expert: No evidence virus transmitted via aerosols

According to medical expert and researcher with the Chinese Center for Disease Control and Prevention Feng Luzhao, there is no definitive answer as to whether the novel coronavirus can be transmitted via aerosols to date.

virus transmission

Aerosol transmission refers to the mixing of the virus with droplets in the air to form aerosols, which causes infection over larger distances after inhalation.

Direct transmission refers to the infection caused by inhalation of air close to a patient who sneezes and coughs.

Contact transmission occurs when a person touches an object tainted with droplets containing the virus before infecting himself through subsequent contact with the membranes of his mouth, nose, and eyes.

Why is answering this question difficult and why is it a big deal? 

In an article published in nature.com, Smieszek and Lazzari suggest that aerosol transmission is the dominant mode of transmission in long-term epidemics, whereas larger droplets could play a dominant role for short-term epidemics with high attack rates.

According to Tellier,R., Li, Y., Cowling, B.J. et al. in an article published in biomedcentral.com, “although short-range large-droplet transmission is possible for most respiratory infectious agents, deciding on whether the same agent is also airborne has a potentially huge impact on the types (and costs) of infection control interventions that are required.”

One of the reasons that it’s not an easy question to answer is that the term “aerosol” is essentially a relative and not an absolute term.

A lot depends on the environment.

A larger droplet can remain airborne for longer in situations where strong airflows can sustain the suspension effectively enough to cause infection at a considerable distance away from the source.

Additionally in crowded conditions with poor ventilation (in hospital waiting rooms, lecture theatres, on public transport, etc.), explosive outbreaks can still occur, even with pathogens whose airborne transmission capacity is considered to be low, e.g. the spread of influenza in a grounded plane where multiple secondary cases were observed in the absence of any ventilation.

According to Feng Luzhao, there is no need for the public to panic since no evidence shows that the new virus could be contracted by aerosols, adding that the most common transmission routes of the novel coronavirus are found during direct transmission, which is caused by inhalation of air close to a patient who sneezes and coughs.

As a precaution the government has urged residents to avoid gatherings, open windows to help with ventilation, practice good personal hygiene and regularly disinfect their homes, especially areas like door handles, dinner tables, light switches and even faucets/taps.

Feng also said that the possibility of getting infected by consuming fruits and vegetable contaminated by the virus via direct transmission or contact transmission is considered relatively low.

Sources: China Daily, biomedcentral.com, nature.com

Related article: Viruses: discovery, size, structure and how they infect people

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