Aerosol, droplet, airborne – updates need clearer language and examples.
Here’s what I got from doing research to differentiate the modes of transmission after reading a China Daily/Asian news network story indicating the nCOV can spread through aerosol transmission.
SHANGHAI, China – – Confirmed transmission routes of the novel coronavirus include direct transmission, contact transmission, and aerosol transmission, a Shanghai official said on Saturday.
“Aerosol transmission refers to the mixing of the virus with droplets in the air to form aerosols, which causes infection after inhalation, according to medical experts,” said Zeng Qun, deputy head of the Shanghai Civil Affairs Bureau.
“As such, we have called on the public to raise their awareness of the prevention and control of the disease caused by family gatherings,” said Zeng at a daily media briefing by the municipal government regarding efforts to contain the spread of the virus.
Aerosol is NOT the same as airborne, according to plenty of medical websites. Sharing the clearest, from Mt Sinai.
“What is transmission by droplet contact?
Some diseases can be transferred by infected droplets contacting surfaces of the eye, nose, or mouth. This is referred to as droplet contact transmission. Droplets containing microorganisms can be generated when an infected person coughs, sneezes, or talks. Droplets can also be generated during certain medical procedures, such as bronchoscopy. Droplets are too large to be airborne for long periods of time, and quickly settle out of air.
(Me: most websites share info on this in the context of reducing risks to medical workers.)
“Droplet transmission can be reduced with the use of personal protective barriers, such as face masks and goggles. Measles and SARS are examples of diseases capable of droplet contact transmission.
(Me: This was before nCOV, which we now know as more infectious than SARS)
» What is airborne transmission?
“Airborne transmission refers to situations where droplet nuclei (residue from evaporated droplets) or dust particles containing microorganisms can remain suspended in air for long periods of time. These organisms must be capable of surviving for long periods of time outside the body and must be resistant to drying. Airborne transmission allows organisms to enter the upper and lower respiratory tracts. Fortunately, only a limited number of diseases are capable of airborne transmission.
Diseases capable of airborne transmission include:
Tuberculosis
Chickenpox
Measles
(Me: Have no idea if the report from Shanghai will affect DoH policies.
The latest update by the Singapore prime minister noted that increasing local transmissions not linked to Chinese nationals from affected areas spurred the decision to go Orange.
So far, most of our cases have either been imported from China, or can be traced to imported cases. When we discover them, we have isolated the patients, done contact tracing and quarantined close contacts. This has contained the spread and helped stamp out several local clusters. But in the last few days, we have seen some cases which cannot be traced to the source of infection. These worried us, because it showed that the virus is probably already circulating in our own population. This is why we raised the DORSCON to Orange yesterday, and are stepping up measures. We are reducing mingling in schools. We are tightening up access to our hospitals. We are taking extra precautions at large public events. I have already postponed my Chinese New Year Istana Garden Party for grassroots leaders, which was to be held tomorrow. We have raised DORSCON to Orange before. You may not remember, but this was in 2009, for the H1N1 swine flu. So there is no need to panic. We are not locking down the city or confining everybody to stay at home. We have ample supplies, so there is no need to stock up with instant noodles, tinned food, or toilet paper, as some people did yesterday.
Whatever the situation, we can each do our part. One, observe personal hygiene – wash your hands often, and avoid touching your eyes or face unnecessarily. Two, take your temperature twice daily. And three, if you are not well, please avoid crowded places and see a doctor immediately. These simple steps do not take much effort, but if we all do them, they will go a long way towards containing the spread of the virus.
Right now, we are continuing to do contact tracing and to quarantine close contacts. But I expect to see more cases with no known contacts in the coming days.”
– read more here https://www.pmo.gov.sg/Newsroom/PM-Lee-Hsien-Loong-on-the-Novel-Coronavirus-nCoV-Situation-in-Singapore-on-8-February-2020
At any rate, I hope health officials everywhere explain medical terms in more understandable language with examples. Had to go check several sites before getting clearer understanding.
And this is also one of the clearest guides, a video by a Toronto physician https://www.facebook.com/650457506/posts/10157054434187507/?d=n
