The Common Cold Project began in 2011 with the aim of creating, documenting, and archiving a database that combines final research data from 5 prospective viral-challenge studies that were conducted over the preceding 25 years: the British Cold Study (BCS); the three Pittsburgh Cold Studies (PCS1, PCS2, and PCS3); and the Pittsburgh Mind-Body Center Cold Study (PMBC). These unique studies assessed predictor (and hypothesized mediating) variables in healthy adults aged 18 to 55 years, experimentally exposed them to a virus that causes the common cold, and then monitored them for development of infection and signs and symptoms of illness.