Seroconversion rates to 2009 pandemic influenza A H1N1 virus (pH1N1/2009) according to age and time of first sample (S1) collection, CoPanFlu-RUN cohort, Reunion Island, 2009.

Data are numbers, percentages (95% confidence intervals) and ALR parameter test P value for comparison of seroconversion proportions according to time of first sample (S1) collection at inclusion, in each age group, after controlling for household selection. In the group “All ages”, rates of seroconversion were standardized according to age structure of the community. NA: not assessed. Seroconversion was defined as a shift from seronegative at inclusion (i.e. HIA titer