Study population
The study is based on the Epidemiological study on the Genetics and Environment of Asthma (EGEA) cohort, which combines a group of asthma cases recruited in chest clinics with their first-degree relatives and a group of population-based participants. At baseline (EGEA1), 2047 individuals (both children and adults) were recruited in 1991-1995 in five French cities. A first follow-up (EGEA2) was set-up in 2003-2007, including 1845 individuals from EGEA1 and 58 new family members. Virus-specific IgG responses were measured in 2021 in a subsample of 531 children (530 with valid measure) from the EGEA1 survey and 1360 adults (1241 with valid measure) from the EGEA2 survey. Among them, 329 individuals (270 with valid measure) had IgG responses measured in both EGEA1 and EGEA2 surveys. Written informed consent was obtained from all adult participants and child’s legal guardians at both surveys; and ethical approvals were obtained from the ethics committees (Cochin Royal Hospital, Paris for EGEA1 and Necker-Enfants Malades Hospital, Paris for EGEA2).