Fig 1. A box plot of the mean concentration of cord blood titres of cases and controls by age categories.

Differences in the mean concentration of maternally transferred respiratory syncytial virus (RSV) specific antibodies (log₂PRNT titres) from cord blood samples (with P values shown), between cases and controls at age categories in months of first RSV infection; 1–2 and 3–5. Cases were matched to controls in a ratio of 1:2. P values generated using a two sample paired t-test.