Ceuppens, J. L., Bullens, D., Kleinjans, H., Van Der Werf, J. and the PURETHAL Birch Efficacy Study Group (2009), Immunotherapy with a modified birch pollen extract in allergic rhinoconjunctivitis: clinical and immunological effects. Clin Exp Allergy 2009; 39: 1903–9.
In this study, patients were evaluated during the pollen season by a combined symptom and medication score (CIS), and medians of the CIS values are presented (tables 1 and 2, and text) after treatment with verum or placebo.
In the text, percentages are given for the differences between groups (verum treatment compared to placebo), referring to the tables. The percentages were calculated on the basis of mean CIS values (as originally presented to the journal), instead of the medians, added during editorial review of the manuscript.
Therefore the following corrections should be applied: