Studies to date by the WHO suggest that the virus causing COVID-19 is transmitted mainly by contact with respiratory droplets, rather than by air.
This implies that there is no contagion from breathing on the street or in a supermarket. Although it seems that this does not require wearing masks as a personal protection measure, the advice of local health experts is that if someone does not know that they are infected and asymptomatic, wearing a mask can avoid infecting others.
According to the WHO, being less than a meter away from a person with respiratory symptoms, such as coughing or sneezing, does pose a risk of contagion. At that distance, we are exposed to respiratory droplets with infective capacity, between 5 and 10 microns – a human hair is more than 100 microns in diameter. These particles remain suspended in the air when someone sneezes or coughs and then fall to the ground under their own gravity, so a person located nearby during that short period of time can become infected.
How to protect yourself
- Stay at least 1 meter apart from others
- Frequently disinfect surfaces
- Wash your hands with soap and water at least 8 times a day for 20 to 60 seconds
- Avoid touching eyes, nose and mouth
How long does coronavirus last on surfaces?
You can also do this by touching a surface in the immediate environment of the sick person on which some of those larger particles have been deposited or objects used with people with coronavirus. Hence the importance of washing hands after touching a surface in a public space, such as handrails, door handles, etc.
For weeks, experts have argued that the virus is not transmitted through the air. But in fact, it can travel through the air and remain suspended for about half an hour.
The researchers argue that when the virus is suspended in droplets of less than 5 microns – known as aerosols – it can be suspended for about half an hour before descending and settling on surfaces, where it can remain for several hours.
- In plastic and stainless steel: up to 72 hours
- In copper: 4 hours.
- On cardboard: up to 24 hours
The drops they infect do not go beyond a meter, and that is why this separation between people must be respected, according to WHO advice. (I)