Just when we have gotten used to social distancing 6 feet from each other to slow the spread of COVID-19, scientists from Oxford University and the Massachusetts Institute of Technology suggest that it may not always be enough.
In a new study, researchers found that the virus can travel on respiratory droplets up 26 feet in just a few seconds after someone cough, sneezes, or sings.
The 6-foot guidance is based on an oversimplified scenario that looks at how the virus is transferred by either large or small airborne droplets without accounting for other factors.
Transmission of the virus is more complex. It involves a range of droplet sizes and the activity that propelled the virus through the air. The research team evaluated published studies looking at how far respiratory droplets from the coronavirus that causes COVID-19, as well as from other viruses, can spread in different circumstances.
Based on those findings, they suggest a better model for social distancing guidance is needed. The guidelines should consider the setting, how crowded it is, how long someone is there, and whether people are wearing face coverings.
Using that guide, a poorly ventilated, crowded environment where people are shouting and singing and not wearing face coverings would be high-risk. And an outdoor, well-ventilated, less crowded environment, where people are quiet and wearing face coverings, would be lower-risk.
Taking these factors into account to adjust social distancing guidelines would mean greater protection in high-risk settings, but also greater freedom in lower-risk settings — and perhaps a return toward “normal,” at least in some situations.
Their bottom line: the best social distancing depends on the many things that combine to determine risk of virus transmission.
Transmission risk of COVID-19 depends very much on circumstances. Indoor is much more risky than outdoor. Particle size matters, if it’s smaller, it can travel faster.
Risk depends on your activity, the motion of the air in the room, humidity and how long you are actually in the room. The viral load – or level of virus within a person’s airways — also varies from person to person.
The study encourages people to consider all these things when deciding on the amount of social distancing. “If you are wearing a mask, not shouting, not sick, keep your mask on, and there is some indoor ventilation, 6 feet is probably enough.”
It’s important to keep this in mind not only when thinking about physically how far you need to be from others, but also when thinking about which activities are safe.