Serological Responses to 
ELISA-quantified serum antibody titers at day 21 in 40/48 colonized participants were compared with those in 61 randomly selected noncolonized participants (all from the LAIV group due to sera availability). Missing serum was due to insufficient remaining material from the parent study. The age was not significantly different between participants included in serological study who were colonized compared to noncolonized controls (median age in months 36 vs 32, Serological responses to Serological responses to 