Variation in Severe Acute Respiratory Syndrome Coronavirus 2 Bioaerosol Production in Exhaled Breath

We developed a simple, noninvasive mask sampling method to quantify and sequence severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from exhaled breath. We found substantial variation between individuals in SARS-CoV-2 copies exhaled over a 15-minute period, which moderately correlated with nasal swab viral load. Talking was associated with a median of 2 log₁₀ greater exhaled viral copies. Exposure varies substantially between individuals but may be risk stratified by nasal swab viral load and whether the exposure involved conversation.