In PLoS Medicine, volume 4, issue 4, doi:10.1371/journal.pmed.0040074:
The author inadvertently omitted the following citation that addresses the same topic (at the time of publication of the PLoS Medicine article, the article in The Lancet was still in press):
Olusanya BO, Newton VE (2007) Global burden of childhood hearing impairment and disease control priorities for developing countries. Lancet 369: 1314–1317.
The author did, however, cite this Lancet paper, as reference [10], in an earlier Correspondence article published in PLoS Medicine: Olusanya BO (2007) “The Right Stuff”: The Global Burden of Disease. PLoS Med 4(2): e84. doi:10.1371/journal.pmed.0040084