Reading numerous news articles about COVID-19, I got confused as to what is its main transmission route. In particular, I am confused as to whether it is
- direct landing of respiratory droplets in mouths and noses,
- contaminated surfaces,
- aerosols (i.e., suspensions of the virus in the air rather than respiratory droplets quickly landing in mouths or noses or on surfaces), or
- something else.
On the one hand, the website of the Centers for Disease Control and Prevention (CDC) says that contaminated surfaces are not thought to be the main transmission route:
It may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes, but this is not thought to be the main way the virus spreads. (Link)
The same website appears to suggest that the main transmission route is direct landing of respiratory droplets in mouths and noses:
The virus is thought to spread mainly from person-to-person.
Between people who are in close contact with one another (within about 6 feet).
Through respiratory droplets produced when an infected person coughs or sneezes.
These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.
On the other hand, the World Health Organization (WHO), like many other agencies, puts the main emphasis on washing hands. Here is the WHO's first and foremost piece of advice on how to prevent getting infected with the virus:
Regularly and thoroughly clean your hands with an alcohol-based hand rub or wash them with soap and water. Why? Washing your hands with soap and water or using alcohol-based hand rub kills viruses that may be on your hands. (Link)
Social distancing is mentioned on that webpage only as a second piece of advice, and, furthermore, the webpage implies that it is safe to approach coughing people as close as 1 meter away:
Maintain at least 1 metre (3 feet) distance between yourself and anyone who is coughing or sneezing.
Furthermore, I found an article saying that the virus wasn't detected in the air of hospital rooms with COVID-19 patients, but was detected on surfaces:
When researchers in Singapore tested the air in the rooms of three Covid-19 patients, they found no virus particles on cleaned surfaces or in the air even when they took samples on days the patients were symptomatic and presumably shedding virus into the air, they reported this month in the Journal of the American Medical Association. In the room of the third patient, who shed more virus, virus particles were present on ventilation fans and numerous surfaces — but all air samples were negative. (Link)
But the same article also says that Chinese researchers found COVID-19 aerosols near patients' toilets.
My question: Actually what is the main way COVID-19 spreads?