[BostonCard]

Your probability of becoming infected likely follows a sinusoidal dose/response relationship, where "dose" represents the number of viral particles you are exposed to.  At a high enough dose, the probability of being infected is nearly guaranteed; at a low enough dose, you are very unlikely to get sick.

The "dose" is dependent on a number of factors.  First off is how much the infected person is shedding.  Then it depends on where in the respiratory tract the virus is most shed (nasophayngeal shedding results means it is spread by droplets, while lower respiratory infections are aerosolized).  Then it depends a lot on how the virus filled particles are transported (which is based on whether they are breathed out or coughed or sneezed) as well as local ventilation patterns (indoor versus outdoor, winds or fans, etc).  The dose will be dependent on distance from the infected person to the susceptible person and by length of the contact, as well as other behaviors such as mask wearing (reduces risks to others, especially of large droplets generated while coughing/sneezine) and frequent hand washing, to minimize transmission from droplets that settled on the hands to the oropharynx.

All of this is to say that it's complicated and based on a lot of different variables.  Instead of looking at things as absolutes (safe/not safe) it is probably best looked at in a risk minimization sense; how can you minimize the risk to you and others.  Risks cannot be eliminated, but avoiding unnecessary contacts with others, maintaining as large a physical distance between you and others as possible, widespread use of face coverings, strict isolation of sick people, frequent hand-washing, etc. can all reduce risk.

BC

[BostonCard]

Your probability of becoming infected likely follows a sinusoidal dose/response relationship, where "dose" represents the number of viral particles you are exposed to.  At a high enough dose, the probability of being infected is nearly guaranteed; at a low enough dose, you are very unlikely to get sick.

The "dose" is dependent on a number of factors.  First off is how much the infected person is shedding.  Then it depends on where in the respiratory tract the virus is most shed (nasophayngeal shedding results means it is spread by droplets, while lower respiratory infections are aerosolized).  Then it depends a lot on how the virus filled particles are transported (which is based on whether they are breathed out or coughed or sneezed) as well as local ventilation patterns (indoor versus outdoor, winds or fans, etc).  The dose will be dependent on distance from the infected person to the susceptible person and by length of the contact, as well as other behaviors such as mask wearing (reduces risks to others, especially of large droplets generated while coughing/sneezine) and frequent hand washing, to minimize transmission from droplets that settled on the hands to the oropharynx.

All of this is to say that it's complicated and based on a lot of different variables.  Instead of looking at things as absolutes (safe/not safe) it is probably best looked at in a risk minimization sense; how can you minimize the risk to you and others.  Risks cannot be eliminated, but avoiding unnecessary contacts with others, maintaining as large a physical distance between you and others as possible, widespread use of face coverings, strict isolation of sick people, frequent hand-washing, etc. can all reduce risk.

BC