New publication in the British Medical Journal presents a model that summarizes and extends the available data on risk levels associated with various situations, for example short or prolonged contact times, low or high occupancy spaces, indoors or outdoors, good or bad ventilation, wearing a mask or not, and being silent, or speaking, or shouting/singing, or heavy exercise. As you might guess, the lowest risk is in an outdoors, well-ventilated space that has low occupancy, short-contact times, while wearing a mask; the highest risk is no masks, indoors in a poorly ventilated high-occupancy space, while doing heavy exercise.
- It would be wrong, based on this, to say that masks have no effect; it would also be wrong to say that masks are all you need to lower your risk level.
- Your best strategy is to avoid high-occupancy spaces (especially indoors) and prolonged contacts, and to wear a mask.