Does the effect of vitamin A supplements depend on vaccination status? An observational study from Guinea-Bissau
Ane B Fisker, Peter Aaby, Carlito Bale, Ibraima Balde, Sofie Biering-Sørensen, Jane Agergaard, Cesario Martins, Bo M Bibby, Christine S Benn
BMJ Open Jan 2012, 2 (1) e000448; DOI: 10.1136/bmjopen-2011-000448