- Simple breathing can spread COVID-19 from individuals who appear well.
- The easy transmission of this virus changes how we will try to limit the pandemic.
Reports are emerging that even regular breathing can transmit COVID-19. The virus appears to be in expired air from people who are just breathing normally. This is very different from SARS or from other coronavirus infections where coughing is necessary. How has this happened?
As I blogged a few days ago, COVID-19 has evolved very quickly in humans. COVID-19 binds to receptors on respiratory cells much stronger than SARS. This allows the virus to replicate in the nose and the throat as compared to only being produced in the lungs with SARS.
With SARS, therefore, one needs to cough to aerosol the virus and infect others because the virus is only present deep in the lung. In contrast, with COVID–19 the virus is present and replicating in the nose and throat; this means simple breathing will flush it out into the air to infect others.
It is a remarkable bit of evolution on the part of the virus; this allows the virus to increase the infection of the human population by having otherwise healthy people, who have no cough or obvious symptoms, transmit the virus. The world-wide pandemic is a direct result of the increased infectivity of COVID-19.
We must remember people who are healthy and don’t have a cough can still transmit COVID-19. Since approximately 20 to 40%of COVID-19 infected individuals don’t display symptoms and patients also are able to spread the infection early on before they become sick, almost anyone can infect you.
There are two important implications from this.
Everyone should wear a mask of some sort. These masks will capture your breathing and prevent the virus in your breath from infecting other people. Remember, wearing a mask is not to protect yourself but to protect others from your asymptomatic spread of the virus.
Virus testing won’t help at this point. The criteria for virus testing exclude people without symptoms and will not prevent their spread of the virus at this time. Since asymptomatic people are probably a common source of infection, doing screening for virus may help identify those who need to be hospitalized but won’t prevent spread by asymptomatic individuals.
Therefore, at this point in time we should focus on masks and not viral screening as a means to limit the COVID-19 pandemic.