In the results section of the abstract in the online (full) version of this paper by M van Veen and colleagues (*BMJ* 2008;337:a1501, doi:10.1136/bmj.a1501, published 22 September) the likelihood ratio of 2.4 is for children aged 0-2 months (not 0-3 months as stated).

Cite this as: *BMJ* 2008;337:a1849
