The type and number of chemicals in exhaled breath are different in people with infection as compared to those without infection. In this study, the breath of people with and without COVID infection will be measured. Changes in the amount and type of chemicals in breath will be used to determine if an individual does or does not have COVID infection. If the measurements of breath are a reliable measure of COVID infection, this device may be used to rapidly screen people who are attending large public events (for example, music concert or baseball game) to minimize the spread of COVID at the event.