A: We still believe that the virus is transmitted primarily through droplets. But, here’s the truth: there is a very fine line between droplet and airborne transmission.
Airborne: Transmitted by tiny droplets that remain suspended in the air. Can travel distances. (Hypothesized for SARS and MERS)
Droplet: Transmitted by larger droplets that fall to the ground within a few feet. Transmitted by coughing, sneezing. (Why we often use the six feet apart rule). (Think common cold, influenza).
We can think of airborne transmission (to simplify) as a more extreme form of droplet transmission rather than think of it as a completely separate mode of transmission.
Recent research has suggested that airborne transmission may be possible, however much of the research has been studied in clinical settings. Even if viral fragments are found in suspended air droplets, we are not sure if this implies that the virus can be transmitted. Still, evidence suggests that even loud speaking in a closed environment could influence transmission.
Overall the ability to spread this way is influenced by infectiousness (that R-naught we talked about!), how much of the virus a person transmits (based on proximity, how much is in each droplet, and influencing events like singing), and ventilation (think subways and waiting rooms).
The good news: Our current public health measures are still protecting us from the events where airborne transmission may increase risk. It just may help us to identify the events where people are most likely to spread so that interventions can also target those events.
Q: And why do some people get some symptoms and others not? Is the virus changing?
A: Some people have gastrointestinal symptoms while others seem to even have cardiac symptoms. Not to fear. This is a new virus and so we are studying it very deeply. There are also varying symptoms in influenza although overall clinical presentation in influenza is more uniform. Two theories about COVID-19: 1) It uses the lungs to spread itself throughout the body, impacting other systems and 2) It binds to the ACE2 surface protein, which is present among many organs and systems including the kidneys, heart, and gastrointestinal tract. Influenza on the other hand, relies primarily on the upper respiratory tract to take hold.
The point: It is good that we learn more about these various manifestations of disease. And so it is great that the CDC has broadened its symptom profile for COVID-19. Because the more the public knows about symptoms, the sooner they can get treatment. But, no, the virus isn’t tricking us, just showing us its full profile as we gather information every day.
The bottom line: We learn more every day. Then we adapt. As of now, airborne transmission does not change most states’ guidelines. And the presentation of COVID-19 as varied only helps you know what symptoms you might have that align with COVID-19 and prompt you to get a test even sooner.
Stay well!
#stayhome #Covid-19 #coronavirus
