Discussion
To the best of our knowledge, this study is the first to investigate the
associations of personal and seasonal factors with IgG levels to RSV and
RV viruses in a large population of children and adults. Results showed
that an older age was associated with higher RV-specific IgG levels in
children (aged between 2-16 years) and lower RV-specific IgG level in
adults (aged between 18-79 years) while it was associated with higher
RSV-specific level in both children and adults. RV-specific IgG levels
were higher in women and lower with higher BMI both in children and
adults, while RSV-specific IgG levels were not associated with sex and
BMI. Higher levels of RSV and RV-specific IgG were found during winter,
spring and autumn in adults while no significant association with season
was observed for children. Current smoking, and to a lesser extent
former smoking, were associated with higher IgG levels for RSV and all
RV species in adults whereas passive smoking among children was not
associated with RSV and RV-specific IgG levels. Overall, these results
suggest that different determinants might influence the immune response
to respiratory viruses, according to the respiratory virus (RSV or RV)
and the age (in children or in adults).